Language resource management — Word segmentation of written texts — Part 2: Word segmentation for Chinese, Japanese and Korean

The basic concepts and general principles of word segmentation as defined in ISO 24614-1 apply to Chinese, Japanese and Korean. Text needs to be segmented into tokens, words, phrases or some other types of smaller textual units in order to perform certain computational applications on language resources, such as natural language processing, information retrieval and machine translation. ISO 24614-2:2011 is restricted to the segmentation of a text into words or other word segmentation units (WSUs). This task is distinct from morphological or syntactic analysis per se, although it greatly depends on morphosyntactic analysis. It is also different from the task of laying out a framework for constructing a lexicon and identifying its lexical entries, namely lemmas and lexemes. The frameworks for the latter tasks are provided by ISO 24611, ISO 24613 and ISO 24615. ISO 24614-2:2011 specifies rules for delineating WSUs for Chinese, Japanese and Korean. Some rules are common to all three languages, though each language also has its own distinct rules for identifying WSUs. The common features are discussed, then the distinct rules are laid out for Chinese, for Japanese and for Korean.

Gestion des ressources langagières — Segmentation des mots dans les textes écrits — Partie 2: Segmentation des mots pour le chinois, le japonais et le coréen

Upravljanje z jezikovnimi viri - Besedna razčlenitev pisanega besedila - 2. del: Besedna razčlenitev za kitajski, japonski in korejski jezik

Osnovni pojmi in splošna načela besedne razčlenitve, kot je opredeljeno v standardu ISO 24614-1, veljajo za kitajski, japonski in korejski jezik. Besedilo mora biti razčlenjeno na znake, besede, fraze ali nekatere druge vrste manjših besedilnih enot za izvajanje nekaterih računalniških aplikacij za jezikovne vire, kot so jezikovna obdelava naravnega jezika, pridobivanje informacij (IR) in strojno prevajanje (MT). Ta del standarda ISO 24614 je omejen na razčlenitev besedila na besede ali druge besedne razčlenitvene enote (WSUs). Ta naloga se razlikuje od oblikoslovne in skladenjske analize, čeprav je v veliki meri odvisna od oblikoslovno-skladenjske analize. Prav tako se razlikuje od določanja okvirja za izgradnjo leksikona in določanje leksikalnih vnosov, in sicer lem in leksemov. Osnovo za ti dve nalogi ponujajo standardi ISO 24611, ISO 24613 in ISO 24615. Glavni cilj tega dela standarda ISO 24614 je določiti pravila za razmejevanje besednih razčlenitvenih enot za kitajski, japonski in korejski jezik. Nekatera pravila so skupna vsem trem jezikom, vendar ima vsak jezik tudi lastna pravila za določanje besednih razčlenitvenih enot. Skupne značilnosti so obravnavane v točki 5, posebna pravila pa so določena v točki 6 za kitajski jezik, točki 7 za japonski in točki 8 za korejski jezik.

General Information

Status
Published
Publication Date
24-Aug-2011
Current Stage
9093 - International Standard confirmed
Start Date
08-Dec-2017
Completion Date
08-Dec-2017

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SLOVENSKI STANDARD
SIST ISO 24614-2:2014
01-september-2014
Upravljanje z jezikovnimi viri - Besedna razčlenitev pisanega besedila - 2. del:
Besedna razčlenitev za kitajski, japonski in korejski jezik
Language resource management - Word segmentation of written texts - Part 2: Word
segmentation for Chinese, Japanese and Korean

Gestion des ressources langagières - Segmentation des mots dans les textes écrits -

Partie 2: Segmentation des mots pour le chinois, le japonais et le coréen
Ta slovenski standard je istoveten z: ISO 24614-2:2011
ICS:
01.020 Terminologija (načela in Terminology (principles and
koordinacija) coordination)
01.140.10 Pisanje in prečrkovanje Writing and transliteration
SIST ISO 24614-2:2014 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ISO 24614-2:2014
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SIST ISO 24614-2:2014
INTERNATIONAL ISO
STANDARD 24614-2
First edition
2011-09-01
Language resource management — Word
segmentation of written texts —
Part 2:
Word segmentation for Chinese,
Japanese and Korean
Gestion des ressources langagières — Segmentation des mots dans
les textes écrits —
Partie 2: Segmentation des mots pour le chinois, le japonais et le
coréen
Reference number
ISO 24614-2:2011(E)
ISO 2011
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SIST ISO 24614-2:2014
ISO 24614-2:2011(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2011

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2011 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 24614-2:2014
ISO 24614-2:2011(E)
Contents Page

Foreword ............................................................................................................................................................. v

Introduction ........................................................................................................................................................ vi

1 Scope ...................................................................................................................................................... 1

2 Normative references ............................................................................................................................ 1

3 Terms and definitions ........................................................................................................................... 2

4 Overview ................................................................................................................................................. 4

4.1 Introduction ............................................................................................................................................ 4

4.2 Markup convention ................................................................................................................................ 4

4.3 Review of the concept of word segmentation unit ............................................................................ 5

4.4 Features common to Chinese, Japanese and Korean ....................................................................... 5

5 General rules for identifying WSUs in Chinese, Japanese and Korean .......................................... 6

5.1 Words ...................................................................................................................................................... 6

5.2 Derivationally formed words ................................................................................................................ 6

5.3 Word compounds .................................................................................................................................. 7

5.4 Phrasal compounds .............................................................................................................................. 8

5.5 Idioms ..................................................................................................................................................... 8

5.6 Fixed expressions ................................................................................................................................. 9

5.7 Abbreviations ....................................................................................................................................... 10

5.8 Transliterated loanwords .................................................................................................................... 10

5.9 Strings of foreign or special characters ........................................................................................... 11

5.10 Components of a WSU ........................................................................................................................ 11

6 Specific rules for identifying WSUs in Chinese ............................................................................... 12

6.1 Lexical items followed by the suffix儿(r) .......................................................................................... 12

6.2 Lexical items ........................................................................................................................................ 12

6.2.1 Nouns .................................................................................................................................................... 12

6.2.2 Verbs ..................................................................................................................................................... 17

6.2.3 Adjectives ............................................................................................................................................. 20

6.2.4 Pronouns .............................................................................................................................................. 22

6.2.5 Numerals .............................................................................................................................................. 23

6.2.6 Measure words .................................................................................................................................... 25

6.2.7 Adverbs ................................................................................................................................................ 25

6.2.8 Prepositions ......................................................................................................................................... 26

6.2.9 Conjunctions ........................................................................................................................................ 26

6.2.10 Auxiliary words .................................................................................................................................... 26

6.2.11 Modal words ......................................................................................................................................... 27

6.2.12 Exclamations ....................................................................................................................................... 27

6.2.13 Imitative words .................................................................................................................................... 27

7 Specific rules for identifying WSUs in Japanese text ..................................................................... 27

7.1 Bunsetsus ............................................................................................................................................ 27

7.2 Lexical items ........................................................................................................................................ 27

7.2.1 General rule .......................................................................................................................................... 27

7.2.2 Nouns .................................................................................................................................................... 28

7.2.3 Verbs ..................................................................................................................................................... 32

7.2.4 Adjectives ............................................................................................................................................. 33

7.2.5 Adnouns ............................................................................................................................................... 34

7.2.6 Adverbs ................................................................................................................................................ 34

7.2.7 Conjunctions ........................................................................................................................................ 35

7.2.8 Exclamations ....................................................................................................................................... 35

© ISO 2011 – All rights reserved iii
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7.2.9 Particles ................................................................................................................................................35

7.2.10 Auxiliary verbs .....................................................................................................................................35

8 Specific rules for identifying WSUs in Korean text ..........................................................................36

8.1 Eojeols ..................................................................................................................................................36

8.2 Lexical items ........................................................................................................................................36

8.2.1 General rule ..........................................................................................................................................36

8.2.2 Nouns ....................................................................................................................................................37

8.2.3 Pronouns ..............................................................................................................................................38

8.2.4 Numerals ...............................................................................................................................................39

8.2.5 Verbs .....................................................................................................................................................39

8.2.6 Adjectives .............................................................................................................................................39

8.2.7 Adnouns ...............................................................................................................................................40

8.2.8 Adverbs .................................................................................................................................................40

8.2.9 Exclamations ........................................................................................................................................40

8.3 Grammatical affixes .............................................................................................................................40

Annex A (informative) Comparative table of parts of speech in Chinese, Japanese and Korean ............42

Bibliography ......................................................................................................................................................43

iv © ISO 2011 – All rights reserved
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SIST ISO 24614-2:2014
ISO 24614-2:2011(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 24614-2 was prepared by Technical Committee ISO/TC 37, Terminology and other language and content

resources, Subcommittee SC 4, Language resource management.

ISO 24614 consists of the following parts, under the general title Language resource management — Word

segmentation of written texts:
 Part 1: Basic concepts and general principles
 Part 2: Word segmentation for Chinese, Japanese and Korean
© ISO 2011 – All rights reserved v
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ISO 24614-2:2011(E)
Introduction

This part of ISO 24614 focuses on word segmentation in Chinese, Japanese and Korean written texts. As far

as typography is concerned, there is no white space between words in Chinese, Japanese or pre-modern

Korean texts. This makes it hard to segment a text into words, unless there is a consistent way of identifying

word segmentation units for those languages. On the other hand, in modern-day Korean text, word forms or

verbal stems that are agglutinated with grammatical affixes, called ‘eojeol’ or ‘malmadi’, are separated by

white space as in English written texts. Hence, it is much easier to identify words or other word segmentation

units in a Korean text. Nevertheless, a large number of words in Korean as well as in Japanese are borrowed

or derived from Chinese words; their internal structures are also based on the word formation principles of

Chinese. As a consequence, general rules for identifying word segmentation units (WSUs) in Chinese,

especially internal WSUs embedded in larger WSUs, are also applicable to some extent to the processing of

Japanese and Korean texts.

The use of characters does not play a real role in identifying WSUs in a text. Many Korean words can be

written either in Chinese or in Korean characters, but the same principles of analysing Chinese-derived words

and identifying sub-WSUs of those words apply. A newspaper published in Beijing is written in simplified

Chinese characters, while a Hong Kong newspaper may be written in traditional Chinese characters. Here

again, the same principles of identifying WSUs apply to both newspapers.

This part of ISO 24614 first sets out the general rules for identifying WSUs in Chinese, Japanese and Korean,

then addresses the specific rules for each language.
vi © ISO 2011 – All rights reserved
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SIST ISO 24614-2:2014
INTERNATIONAL STANDARD ISO 24614-2:2011(E)
Language resource management — Word segmentation of
written texts —
Part 2:
Word segmentation for Chinese, Japanese and Korean
1 Scope

The basic concepts and general principles of word segmentation as defined in ISO 24614-1 apply to Chinese,

Japanese and Korean. Text needs to be segmented into tokens, words, phrases or some other types of

smaller textual units in order to perform certain computational applications on language resources, such as

natural language processing, information retrieval (IR) and machine translation (MT). This part of ISO 24614 is

restricted to the segmentation of a text into words or other word segmentation units (WSUs). This task is

distinct from morphological or syntactic analysis per se, although it greatly depends on morphosyntactic

analysis. It is also different from the task of laying out a framework for constructing a lexicon and identifying its

lexical entries, namely lemmas and lexemes. The frameworks for the latter tasks are provided by ISO 24611,

ISO 24613 and ISO 24615.

The main objective of this part of ISO 24614 is to specify rules for delineating WSUs for Chinese, Japanese

and Korean. Some rules are common to all three languages, though each language also has its own distinct

rules for identifying WSUs. The common features are discussed in Clause 5, then the distinct rules are laid out

in Clause 6 for Chinese, Clause 7 for Japanese and Clause 8 for Korean.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.
ISO 24611, Language resource management — Morpho-syntactic annotation framework
ISO 24613:2008, Language resource management — Lexical markup framework (LMF)

ISO 24614-1:2010, Language resource management — Word segmentation of written texts — Part 1: Basic

concepts and general principles
© ISO 2011 – All rights reserved 1
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ISO 24614-2:2011(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 24611, ISO 24613 and ISO 24614-1

and the following apply.
3.1
adnoun
ADN
non-conjugating word that modifies a noun
NOTE Adnouns modify nouns, as adverbs modify verbs.
EXAMPLE 1
a. あらゆる 国
arayuru kuni
ADN N
‘every country’
b. 好きな 花
suki+na hana
ADNst+SX N
‘favourite flower’
EXAMPLE 2
a. 새 옷
sae ot
ADN noun
‘new clothes’
b. 빨간 옷
bbalga+n ot
ADJst+GX N
‘red clothes’
3.2
bunsetsu
phrase (3.8) without internal modifying relations

EXAMPLE The sentence 私は学校へ早く行きました(I went to school early) consists of four bunsetsus:

私は(watashiwa), 学校へ (gakkoue), 早く(hayaku) and 行きました(ikimashita) in which
私(watashi) is a pronoun,
は(wa) is a particle,
学校(gakkou) is a noun,
へ(e) is a particle,
早く(hayaku) is an adjective in adverbial usage,
行き(iki) is a verbal stem followed by
まし(mashi) is an auxiliary verb denoting politeness, and
た(ta) is an auxiliary verb indicating the past tense.

NOTE A bunsetsu normally consists of a noun plus its particle(s) or a verb plus its ending(s), auxiliary verb(s) or

particle(s) as shown in the example above.
2 © ISO 2011 – All rights reserved
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ISO 24614-2:2011(E)
3.3
ending
agglutinative affix of a verb or adjective

NOTE Verbs and adjectives end with agglutinative forms, called “endings”. These endings may be a negative form,

an adverbial form, a base form, an adnominal form, an assumption form or an imperative form.

3.4
eojeol
malmaldi

word or its variant word form agglutinated with grammatical affixes

NOTE 1 White space (space between characters) helps to segment text into eojeols.

EXAMPLE
내가 사과를 먹었다
nae+ga sagwa+reul meok+eot+da
pronoun+GX noun+GX Vst+GX+GX
‘I’+SBJ ‘apple’+OBJ ‘eat’+PST+DCL = ‘I ate (an) apple’

NOTE 2 This sentence consists of three eojeols: 내가, 사과를 and 먹었다, each of which is separated by white space.

The acronyms GX, SBJ, OBJ, PST and DCL in the example above stand for grammatical affix, subject, object, past tense

and declarative sentential type, respectively. The pronoun 내 is a variant form of the pronoun 나 referring to the speaker.

먹었다 is an eojeol and at the same time is a word form agglutinated with two grammatical affixes 었 and 다 to a verb

stem .
3.5
lexical item
entry in a lexicon that is a lexeme or one of its variant forms

NOTE Headed by a lemma, each lexical item may be either a free-standing word (or one of its variant word forms) or

a bound (non-free-standing) form such as stems and affixes. See ISO 24614-1:2010 for the definitions of lexeme, lemma

and lexicon.
3.6
measure word

part of speech defining, along with numbers, the quantity of a given object, or identifying

specific objects with demonstrative pronouns such as “this” and “that”

NOTE 1 Whereas English speakers say “one person” or “this person”, Chinese speakers say respectively 一个人(yi ge

ren; numeral + measure word + noun; one person) or 这个人 (zhe ge ren; demonstrative pronoun + measure word +

person; this person), where 个 (ge) is a measure word.

NOTE 2 A set of “verbal measure words” is used to count the number of times an action occurs, rather than the

number of items. For example, in the sentence 我去过三次北京(wo qu guo san ci Beijing; pronoun + verb + auxiliary word

+ numeral + measure word + proper noun; I have been to Beijing three times), the 次(ci) functions as a measure word to

combine with a numeral 三 to derive the adverb三次 (sanci) that modifies the verb 去(qu).

3.7
particle

grammatical affix agglutinated mostly to nominal forms but sometimes to other free-standing

lexical items (3.5)
NOTE The grammatical category particle can be treated as a part of speech.

EXAMPLE The noun phrase 学校へ(gakkoue) is analysed into a noun 学校 (gakkou) and a particle へ(e). The verb

phrase 寒いね(samuine, ‘It is very cold, isn't it?’) is analysed into a verb 寒い (samui) and a particle ね(ne) which

corresponds to the tag ‘isn't it ?’.
© ISO 2011 – All rights reserved 3
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SIST ISO 24614-2:2014
ISO 24614-2:2011(E)
3.8
phrase

group of words that perform a grammatical function and that form a conceptual unit within a sentence

4 Overview
4.1 Introduction

This clause first introduces a markup convention for word segmentation units, then reviews the concept of

word segmentation unit (WSU) which was introduced in ISO 24614-1. Some features shared by Chinese,

Japanese and Korean are discussed in 4.3. A comparative table of parts of speech is given in Annex A.

4.2 Markup convention

The following clauses contain a very large number of examples of WSUs. A simple way of representing WSUs

is introduced here.

NOTE This markup convention is introduced here just for the sake of simple illustration in this part of ISO 24614.

First, a stand-off annotation is adopted; this allows primary data to be kept intact from markup notations.

(More information on linguisitic annotation can be found in ISO 24612.) Exceptions are made concerning this

requirement when primary data in Chinese or some other language are not provided with a romanized version

or when the identification of syllables is not easy.
Second, a citation format consisting of four lines is adopted.
 Line 1 introduces primary text fragment in its original script.
 Line 2 represents annotated fragment in romanized form.
 Line 3 assigns morpho-syntactic descriptions.
 Line 4 provides an English equivalent.

The following symbols are used (optionally) for marking up primary data in a romanized form:

1) the dot ‘.’ for syllable boundaries, if ambiguity arises;
2) the sign ‘+’ (plus) for boundaries between a word and an affix;
3) the underscore ‘_’ for word segmentation units (WSUs);
4) the square brackets ‘[ ]’ for WSUs, if ambiguity arises;
5) the parentheses ‘( )’ for non-WSUs;
6) the symbol ‘:=’ represents combined resultant information.
EXAMPLE
헛돌다
[(heot)+dol]_da
prefix + verbStem_GX := verb
‘in vain’ ‘spin’ := ‘to spin in vain’
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ISO 24614-2:2011(E)

The verb 헛돌다 consists of a prefix 헛 (heot) and a verb 돌다 (dol+da). The verb 돌다 is then analysed into a stem 돌

(dol) and a verbal grammatical affix 다 (da). The example 헛돌다 as a whole is a WSU, while its subpart 돌다 is also a

WSU embedded in it. In Korean, as will be discussed, the prefix 헛 (heot) is not treated as a WSU.

For computational purposes, namely character encoding schemes, the characters in Chinese, Japanese and

Korean are all treated as being syllabic. Hence, each of the characters in primary data can easily be identified

with its corresponding romanized string of alphabetic characters. The word given in the above example, for

instance, consists of three syllable characters: 헛, 돌 and 다, while its corresponding romanized version

‘heotdolda’ also consists of three syllables, ‘heot’, ‘dol’ and ‘da’. As a result, we can identify the first syllable

‘heot’ in the romanized version as corresponding to the first syllable 헛 in the Korean example and also the

following sequence of the two syllables in the romanized version as corresponding to the sequence of two

syllable characters 돌다. This indicates that there is no need to mark up primary data, but to keep them intact

in order to show how they are analysed into WSUs or other morphological units.

In Japanese, however, a single Chinese character may be pronounced as more than one syllable: for example,

the noun consisting of one character桜 is pronounced as a three-syllable string ‘sakura’. In such a case,

primary data are marked up.
4.3 Review of the concept of word segmentation unit

Word segmentation is the process of dividing a text into meaningful units called word segmentation units

(WSUs). Each WSU corresponds to a single concept: for example, ‘the White House’ consists of three words

but designates a single concept referring to the residence of the US President. It follows that ‘the White

House’ corresponds to one WSU. In other words, word count and concept do not necessarily correspond, and

may differ from one language to the next. The single English word ‘pork’ is translated by two words that mean

‘pig meat’ in Chinese 猪肉 (zhu_rou), in Japanese豚肉 (buta_niku), and in Korean 돼지고기 (doeji_gogi). So

although English uses only one word and the other languages use two, in all four languages there is just one

WSU.

A unit that carries a meaning that is useful for any linguistic processing can be defined as a WSU. A WSU can

be an entry in a lexicon or any other type of lexical resource insofar as such an entry is leveraged in some

natural language processing application. In other words, the WSU's dimension is more or less fixed, but

linguistic interferences between compounds inside a WSU are not allowed. Such an extensive, open definition

of WSU is useful for further linguistic processing because some WSUs that frequently occur in corpora are not

systematically decomposable by syntactic or any other linguistic processing.
4.4 Features common to Chinese, Japanese and Korean

Two basic features that are common to Chinese, Japanese and Korean derive from a common cultural

heritage in Far East Asia.

 Firstly, Chinese characters have long been used, and continue to be used, in this part of the world

notwithstanding some differences in their degree of use: Chinese utilizes all of these characters, while

Japanese also uses them in addition to Kana characters. On the other hand, Korean has its own writing

system, but sometimes uses Chinese characters, especially for scholarly purposes in humanities such as

classical studies.

 Secondly, many words and phrases of Chinese origin are used in both Japanese and Korean; they

include 四面楚歌 and 第二次世界大战. Note, however, that the non-simplified or original shapes of

Chinese characters are retained in these languages; in the case of Korean, they may simply be written

using the characters of the Korean writing system. The phrase 四面楚歌 written in Chinese characters, for

instance, is written as사면초가 in Korean.

Because of this historical background, some principles of Chinese word segmentation apply significantly to

Chinese-derived words found in Japanese and Korean. If the word is derived from Chinese characters, the

three languages have common properties. If the word is a noun and consists of two or more Chinese

characters, it will constitute a single WSU as long as the characters are “tightly combined and steadily used” in

accordance with the principles set out in ISO 24614-1; for example, ‘each country’ in English is not a single

© ISO 2011 – All rights reserved 5
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SIST ISO 24614-2:2014
ISO 24614-2:2011(E)

WSU, but two WSUs unlike its Chinese equivalent 各国. However, if the final character is productive in a

limited manner, it forms a single WSU with the preceding word; for example, 東京都 (Tokyo Metropolitan), 8月

(August) and 加速器(accelerator) are single WSUs without being analysed into two WSUs, say 東京 and 都.

Because the motivation for a word segmentatio
...

INTERNATIONAL ISO
STANDARD 24614-2
First edition
2011-09-01
Language resource management — Word
segmentation of written texts —
Part 2:
Word segmentation for Chinese,
Japanese and Korean
Gestion des ressources langagières — Segmentation des mots dans
les textes écrits —
Partie 2: Segmentation des mots pour le chinois, le japonais et le
coréen
Reference number
ISO 24614-2:2011(E)
ISO 2011
---------------------- Page: 1 ----------------------
ISO 24614-2:2011(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2011

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2011 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 24614-2:2011(E)
Contents Page

Foreword ............................................................................................................................................................. v

Introduction ........................................................................................................................................................ vi

1 Scope ...................................................................................................................................................... 1

2 Normative references ............................................................................................................................ 1

3 Terms and definitions ........................................................................................................................... 2

4 Overview ................................................................................................................................................. 4

4.1 Introduction ............................................................................................................................................ 4

4.2 Markup convention ................................................................................................................................ 4

4.3 Review of the concept of word segmentation unit ............................................................................ 5

4.4 Features common to Chinese, Japanese and Korean ....................................................................... 5

5 General rules for identifying WSUs in Chinese, Japanese and Korean .......................................... 6

5.1 Words ...................................................................................................................................................... 6

5.2 Derivationally formed words ................................................................................................................ 6

5.3 Word compounds .................................................................................................................................. 7

5.4 Phrasal compounds .............................................................................................................................. 8

5.5 Idioms ..................................................................................................................................................... 8

5.6 Fixed expressions ................................................................................................................................. 9

5.7 Abbreviations ....................................................................................................................................... 10

5.8 Transliterated loanwords .................................................................................................................... 10

5.9 Strings of foreign or special characters ........................................................................................... 11

5.10 Components of a WSU ........................................................................................................................ 11

6 Specific rules for identifying WSUs in Chinese ............................................................................... 12

6.1 Lexical items followed by the suffix儿(r) .......................................................................................... 12

6.2 Lexical items ........................................................................................................................................ 12

6.2.1 Nouns .................................................................................................................................................... 12

6.2.2 Verbs ..................................................................................................................................................... 17

6.2.3 Adjectives ............................................................................................................................................. 20

6.2.4 Pronouns .............................................................................................................................................. 22

6.2.5 Numerals .............................................................................................................................................. 23

6.2.6 Measure words .................................................................................................................................... 25

6.2.7 Adverbs ................................................................................................................................................ 25

6.2.8 Prepositions ......................................................................................................................................... 26

6.2.9 Conjunctions ........................................................................................................................................ 26

6.2.10 Auxiliary words .................................................................................................................................... 26

6.2.11 Modal words ......................................................................................................................................... 27

6.2.12 Exclamations ....................................................................................................................................... 27

6.2.13 Imitative words .................................................................................................................................... 27

7 Specific rules for identifying WSUs in Japanese text ..................................................................... 27

7.1 Bunsetsus ............................................................................................................................................ 27

7.2 Lexical items ........................................................................................................................................ 27

7.2.1 General rule .......................................................................................................................................... 27

7.2.2 Nouns .................................................................................................................................................... 28

7.2.3 Verbs ..................................................................................................................................................... 32

7.2.4 Adjectives ............................................................................................................................................. 33

7.2.5 Adnouns ............................................................................................................................................... 34

7.2.6 Adverbs ................................................................................................................................................ 34

7.2.7 Conjunctions ........................................................................................................................................ 35

7.2.8 Exclamations ....................................................................................................................................... 35

© ISO 2011 – All rights reserved iii
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ISO 24614-2:2011(E)

7.2.9 Particles ................................................................................................................................................35

7.2.10 Auxiliary verbs .....................................................................................................................................35

8 Specific rules for identifying WSUs in Korean text ..........................................................................36

8.1 Eojeols ..................................................................................................................................................36

8.2 Lexical items ........................................................................................................................................36

8.2.1 General rule ..........................................................................................................................................36

8.2.2 Nouns ....................................................................................................................................................37

8.2.3 Pronouns ..............................................................................................................................................38

8.2.4 Numerals ...............................................................................................................................................39

8.2.5 Verbs .....................................................................................................................................................39

8.2.6 Adjectives .............................................................................................................................................39

8.2.7 Adnouns ...............................................................................................................................................40

8.2.8 Adverbs .................................................................................................................................................40

8.2.9 Exclamations ........................................................................................................................................40

8.3 Grammatical affixes .............................................................................................................................40

Annex A (informative) Comparative table of parts of speech in Chinese, Japanese and Korean ............42

Bibliography ......................................................................................................................................................43

iv © ISO 2011 – All rights reserved
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ISO 24614-2:2011(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 24614-2 was prepared by Technical Committee ISO/TC 37, Terminology and other language and content

resources, Subcommittee SC 4, Language resource management.

ISO 24614 consists of the following parts, under the general title Language resource management — Word

segmentation of written texts:
 Part 1: Basic concepts and general principles
 Part 2: Word segmentation for Chinese, Japanese and Korean
© ISO 2011 – All rights reserved v
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ISO 24614-2:2011(E)
Introduction

This part of ISO 24614 focuses on word segmentation in Chinese, Japanese and Korean written texts. As far

as typography is concerned, there is no white space between words in Chinese, Japanese or pre-modern

Korean texts. This makes it hard to segment a text into words, unless there is a consistent way of identifying

word segmentation units for those languages. On the other hand, in modern-day Korean text, word forms or

verbal stems that are agglutinated with grammatical affixes, called ‘eojeol’ or ‘malmadi’, are separated by

white space as in English written texts. Hence, it is much easier to identify words or other word segmentation

units in a Korean text. Nevertheless, a large number of words in Korean as well as in Japanese are borrowed

or derived from Chinese words; their internal structures are also based on the word formation principles of

Chinese. As a consequence, general rules for identifying word segmentation units (WSUs) in Chinese,

especially internal WSUs embedded in larger WSUs, are also applicable to some extent to the processing of

Japanese and Korean texts.

The use of characters does not play a real role in identifying WSUs in a text. Many Korean words can be

written either in Chinese or in Korean characters, but the same principles of analysing Chinese-derived words

and identifying sub-WSUs of those words apply. A newspaper published in Beijing is written in simplified

Chinese characters, while a Hong Kong newspaper may be written in traditional Chinese characters. Here

again, the same principles of identifying WSUs apply to both newspapers.

This part of ISO 24614 first sets out the general rules for identifying WSUs in Chinese, Japanese and Korean,

then addresses the specific rules for each language.
vi © ISO 2011 – All rights reserved
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INTERNATIONAL STANDARD ISO 24614-2:2011(E)
Language resource management — Word segmentation of
written texts —
Part 2:
Word segmentation for Chinese, Japanese and Korean
1 Scope

The basic concepts and general principles of word segmentation as defined in ISO 24614-1 apply to Chinese,

Japanese and Korean. Text needs to be segmented into tokens, words, phrases or some other types of

smaller textual units in order to perform certain computational applications on language resources, such as

natural language processing, information retrieval (IR) and machine translation (MT). This part of ISO 24614 is

restricted to the segmentation of a text into words or other word segmentation units (WSUs). This task is

distinct from morphological or syntactic analysis per se, although it greatly depends on morphosyntactic

analysis. It is also different from the task of laying out a framework for constructing a lexicon and identifying its

lexical entries, namely lemmas and lexemes. The frameworks for the latter tasks are provided by ISO 24611,

ISO 24613 and ISO 24615.

The main objective of this part of ISO 24614 is to specify rules for delineating WSUs for Chinese, Japanese

and Korean. Some rules are common to all three languages, though each language also has its own distinct

rules for identifying WSUs. The common features are discussed in Clause 5, then the distinct rules are laid out

in Clause 6 for Chinese, Clause 7 for Japanese and Clause 8 for Korean.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.
ISO 24611, Language resource management — Morpho-syntactic annotation framework
ISO 24613:2008, Language resource management — Lexical markup framework (LMF)

ISO 24614-1:2010, Language resource management — Word segmentation of written texts — Part 1: Basic

concepts and general principles
© ISO 2011 – All rights reserved 1
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ISO 24614-2:2011(E)
3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 24611, ISO 24613 and ISO 24614-1

and the following apply.
3.1
adnoun
ADN
non-conjugating word that modifies a noun
NOTE Adnouns modify nouns, as adverbs modify verbs.
EXAMPLE 1
a. あらゆる 国
arayuru kuni
ADN N
‘every country’
b. 好きな 花
suki+na hana
ADNst+SX N
‘favourite flower’
EXAMPLE 2
a. 새 옷
sae ot
ADN noun
‘new clothes’
b. 빨간 옷
bbalga+n ot
ADJst+GX N
‘red clothes’
3.2
bunsetsu
phrase (3.8) without internal modifying relations

EXAMPLE The sentence 私は学校へ早く行きました(I went to school early) consists of four bunsetsus:

私は(watashiwa), 学校へ (gakkoue), 早く(hayaku) and 行きました(ikimashita) in which
私(watashi) is a pronoun,
は(wa) is a particle,
学校(gakkou) is a noun,
へ(e) is a particle,
早く(hayaku) is an adjective in adverbial usage,
行き(iki) is a verbal stem followed by
まし(mashi) is an auxiliary verb denoting politeness, and
た(ta) is an auxiliary verb indicating the past tense.

NOTE A bunsetsu normally consists of a noun plus its particle(s) or a verb plus its ending(s), auxiliary verb(s) or

particle(s) as shown in the example above.
2 © ISO 2011 – All rights reserved
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ISO 24614-2:2011(E)
3.3
ending
agglutinative affix of a verb or adjective

NOTE Verbs and adjectives end with agglutinative forms, called “endings”. These endings may be a negative form,

an adverbial form, a base form, an adnominal form, an assumption form or an imperative form.

3.4
eojeol
malmaldi

word or its variant word form agglutinated with grammatical affixes

NOTE 1 White space (space between characters) helps to segment text into eojeols.

EXAMPLE
내가 사과를 먹었다
nae+ga sagwa+reul meok+eot+da
pronoun+GX noun+GX Vst+GX+GX
‘I’+SBJ ‘apple’+OBJ ‘eat’+PST+DCL = ‘I ate (an) apple’

NOTE 2 This sentence consists of three eojeols: 내가, 사과를 and 먹었다, each of which is separated by white space.

The acronyms GX, SBJ, OBJ, PST and DCL in the example above stand for grammatical affix, subject, object, past tense

and declarative sentential type, respectively. The pronoun 내 is a variant form of the pronoun 나 referring to the speaker.

먹었다 is an eojeol and at the same time is a word form agglutinated with two grammatical affixes 었 and 다 to a verb

stem .
3.5
lexical item
entry in a lexicon that is a lexeme or one of its variant forms

NOTE Headed by a lemma, each lexical item may be either a free-standing word (or one of its variant word forms) or

a bound (non-free-standing) form such as stems and affixes. See ISO 24614-1:2010 for the definitions of lexeme, lemma

and lexicon.
3.6
measure word

part of speech defining, along with numbers, the quantity of a given object, or identifying

specific objects with demonstrative pronouns such as “this” and “that”

NOTE 1 Whereas English speakers say “one person” or “this person”, Chinese speakers say respectively 一个人(yi ge

ren; numeral + measure word + noun; one person) or 这个人 (zhe ge ren; demonstrative pronoun + measure word +

person; this person), where 个 (ge) is a measure word.

NOTE 2 A set of “verbal measure words” is used to count the number of times an action occurs, rather than the

number of items. For example, in the sentence 我去过三次北京(wo qu guo san ci Beijing; pronoun + verb + auxiliary word

+ numeral + measure word + proper noun; I have been to Beijing three times), the 次(ci) functions as a measure word to

combine with a numeral 三 to derive the adverb三次 (sanci) that modifies the verb 去(qu).

3.7
particle

grammatical affix agglutinated mostly to nominal forms but sometimes to other free-standing

lexical items (3.5)
NOTE The grammatical category particle can be treated as a part of speech.

EXAMPLE The noun phrase 学校へ(gakkoue) is analysed into a noun 学校 (gakkou) and a particle へ(e). The verb

phrase 寒いね(samuine, ‘It is very cold, isn't it?’) is analysed into a verb 寒い (samui) and a particle ね(ne) which

corresponds to the tag ‘isn't it ?’.
© ISO 2011 – All rights reserved 3
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ISO 24614-2:2011(E)
3.8
phrase

group of words that perform a grammatical function and that form a conceptual unit within a sentence

4 Overview
4.1 Introduction

This clause first introduces a markup convention for word segmentation units, then reviews the concept of

word segmentation unit (WSU) which was introduced in ISO 24614-1. Some features shared by Chinese,

Japanese and Korean are discussed in 4.3. A comparative table of parts of speech is given in Annex A.

4.2 Markup convention

The following clauses contain a very large number of examples of WSUs. A simple way of representing WSUs

is introduced here.

NOTE This markup convention is introduced here just for the sake of simple illustration in this part of ISO 24614.

First, a stand-off annotation is adopted; this allows primary data to be kept intact from markup notations.

(More information on linguisitic annotation can be found in ISO 24612.) Exceptions are made concerning this

requirement when primary data in Chinese or some other language are not provided with a romanized version

or when the identification of syllables is not easy.
Second, a citation format consisting of four lines is adopted.
 Line 1 introduces primary text fragment in its original script.
 Line 2 represents annotated fragment in romanized form.
 Line 3 assigns morpho-syntactic descriptions.
 Line 4 provides an English equivalent.

The following symbols are used (optionally) for marking up primary data in a romanized form:

1) the dot ‘.’ for syllable boundaries, if ambiguity arises;
2) the sign ‘+’ (plus) for boundaries between a word and an affix;
3) the underscore ‘_’ for word segmentation units (WSUs);
4) the square brackets ‘[ ]’ for WSUs, if ambiguity arises;
5) the parentheses ‘( )’ for non-WSUs;
6) the symbol ‘:=’ represents combined resultant information.
EXAMPLE
헛돌다
[(heot)+dol]_da
prefix + verbStem_GX := verb
‘in vain’ ‘spin’ := ‘to spin in vain’
4 © ISO 2011 – All rights reserved
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ISO 24614-2:2011(E)

The verb 헛돌다 consists of a prefix 헛 (heot) and a verb 돌다 (dol+da). The verb 돌다 is then analysed into a stem 돌

(dol) and a verbal grammatical affix 다 (da). The example 헛돌다 as a whole is a WSU, while its subpart 돌다 is also a

WSU embedded in it. In Korean, as will be discussed, the prefix 헛 (heot) is not treated as a WSU.

For computational purposes, namely character encoding schemes, the characters in Chinese, Japanese and

Korean are all treated as being syllabic. Hence, each of the characters in primary data can easily be identified

with its corresponding romanized string of alphabetic characters. The word given in the above example, for

instance, consists of three syllable characters: 헛, 돌 and 다, while its corresponding romanized version

‘heotdolda’ also consists of three syllables, ‘heot’, ‘dol’ and ‘da’. As a result, we can identify the first syllable

‘heot’ in the romanized version as corresponding to the first syllable 헛 in the Korean example and also the

following sequence of the two syllables in the romanized version as corresponding to the sequence of two

syllable characters 돌다. This indicates that there is no need to mark up primary data, but to keep them intact

in order to show how they are analysed into WSUs or other morphological units.

In Japanese, however, a single Chinese character may be pronounced as more than one syllable: for example,

the noun consisting of one character桜 is pronounced as a three-syllable string ‘sakura’. In such a case,

primary data are marked up.
4.3 Review of the concept of word segmentation unit

Word segmentation is the process of dividing a text into meaningful units called word segmentation units

(WSUs). Each WSU corresponds to a single concept: for example, ‘the White House’ consists of three words

but designates a single concept referring to the residence of the US President. It follows that ‘the White

House’ corresponds to one WSU. In other words, word count and concept do not necessarily correspond, and

may differ from one language to the next. The single English word ‘pork’ is translated by two words that mean

‘pig meat’ in Chinese 猪肉 (zhu_rou), in Japanese豚肉 (buta_niku), and in Korean 돼지고기 (doeji_gogi). So

although English uses only one word and the other languages use two, in all four languages there is just one

WSU.

A unit that carries a meaning that is useful for any linguistic processing can be defined as a WSU. A WSU can

be an entry in a lexicon or any other type of lexical resource insofar as such an entry is leveraged in some

natural language processing application. In other words, the WSU's dimension is more or less fixed, but

linguistic interferences between compounds inside a WSU are not allowed. Such an extensive, open definition

of WSU is useful for further linguistic processing because some WSUs that frequently occur in corpora are not

systematically decomposable by syntactic or any other linguistic processing.
4.4 Features common to Chinese, Japanese and Korean

Two basic features that are common to Chinese, Japanese and Korean derive from a common cultural

heritage in Far East Asia.

 Firstly, Chinese characters have long been used, and continue to be used, in this part of the world

notwithstanding some differences in their degree of use: Chinese utilizes all of these characters, while

Japanese also uses them in addition to Kana characters. On the other hand, Korean has its own writing

system, but sometimes uses Chinese characters, especially for scholarly purposes in humanities such as

classical studies.

 Secondly, many words and phrases of Chinese origin are used in both Japanese and Korean; they

include 四面楚歌 and 第二次世界大战. Note, however, that the non-simplified or original shapes of

Chinese characters are retained in these languages; in the case of Korean, they may simply be written

using the characters of the Korean writing system. The phrase 四面楚歌 written in Chinese characters, for

instance, is written as사면초가 in Korean.

Because of this historical background, some principles of Chinese word segmentation apply significantly to

Chinese-derived words found in Japanese and Korean. If the word is derived from Chinese characters, the

three languages have common properties. If the word is a noun and consists of two or more Chinese

characters, it will constitute a single WSU as long as the characters are “tightly combined and steadily used” in

accordance with the principles set out in ISO 24614-1; for example, ‘each country’ in English is not a single

© ISO 2011 – All rights reserved 5
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ISO 24614-2:2011(E)

WSU, but two WSUs unlike its Chinese equivalent 各国. However, if the final character is productive in a

limited manner, it forms a single WSU with the preceding word; for example, 東京都 (Tokyo Metropolitan), 8月

(August) and 加速器(accelerator) are single WSUs without being analysed into two WSUs, say 東京 and 都.

Because the motivation for a word segmentation standard is to recommend which WSUs should be listed in a

given type of lexicon (i.e. not a linguistics lexicon but any kind of practical, indexed container of WSUs), there

may be conflicting principles; for example, principles of non-productivity, frequency and granularity could

trigger conflicts because they are marked by different perspectives for defining WSUs.

Nouns derived from Chinese characters may be shared for the purposes of establishing the WSU structure of

the three languages, but not in every respect. However, Korean and Japanese do have certain features in

common; for example, some Korean verbal affixes and Japanese auxiliary verbs perform the same functions.

Word segmentation in each language varies in line with existing word segmentation rules, and sometimes

even breaches one or more principles of word segmentation. This will be a starting point for recommending a

more synchronized concept of “word segmentation unit” (WSU) in a multilingual environment. The aim of the

concept of “word segmentation unit” is to broaden our view about what could be contained in a lexicon used

for natural language processing purposes, and with little linguistic representation.

5 General rules for identifying WSUs in
...

SLOVENSKI STANDARD
SIST ISO 24614-2:2014
01-september-2014
8SUDYOMDQMH]MH]LNRYQLPLYLUL%HVHGQDUD]þOHQLWHYSLVDQHJDEHVHGLODGHO
%HVHGQDUD]þOHQLWHY]DNLWDMVNLMDSRQVNLLQNRUHMVNLMH]LN
Language resource management - Word segmentation of written texts - Part 2: Word
segmentation for Chinese, Japanese and Korean

Gestion des ressources langagières - Segmentation des mots dans les textes écrits -

Partie 2: Segmentation des mots pour le chinois, le japonais et le coréen
Ta slovenski standard je istoveten z: ISO 24614-2:2011
ICS:
01.140.10 3LVDQMHLQSUHþUNRYDQMH Writing and transliteration
SIST ISO 24614-2:2014 en,fr,de

2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

---------------------- Page: 1 ----------------------
SIST ISO 24614-2:2014
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SIST ISO 24614-2:2014
INTERNATIONAL ISO
STANDARD 24614-2
First edition
2011-09-01
Language resource management — Word
segmentation of written texts —
Part 2:
Word segmentation for Chinese,
Japanese and Korean
Gestion des ressources langagières — Segmentation des mots dans
les textes écrits —
Partie 2: Segmentation des mots pour le chinois, le japonais et le
coréen
Reference number
ISO 24614-2:2011(E)
ISO 2011
---------------------- Page: 3 ----------------------
SIST ISO 24614-2:2014
ISO 24614-2:2011(E)
COPYRIGHT PROTECTED DOCUMENT
© ISO 2011

All rights reserved. Unless otherwise specified, no part of this publication may be reproduced or utilized in any form or by any means,

electronic or mechanical, including photocopying and microfilm, without permission in writing from either ISO at the address below or

ISO's member body in the country of the requester.
ISO copyright office
Case postale 56  CH-1211 Geneva 20
Tel. + 41 22 749 01 11
Fax + 41 22 749 09 47
E-mail copyright@iso.org
Web www.iso.org
Published in Switzerland
ii © ISO 2011 – All rights reserved
---------------------- Page: 4 ----------------------
SIST ISO 24614-2:2014
ISO 24614-2:2011(E)
Contents Page

Foreword ............................................................................................................................................................. v

Introduction ........................................................................................................................................................ vi

1 Scope ...................................................................................................................................................... 1

2 Normative references ............................................................................................................................ 1

3 Terms and definitions ........................................................................................................................... 2

4 Overview ................................................................................................................................................. 4

4.1 Introduction ............................................................................................................................................ 4

4.2 Markup convention ................................................................................................................................ 4

4.3 Review of the concept of word segmentation unit ............................................................................ 5

4.4 Features common to Chinese, Japanese and Korean ....................................................................... 5

5 General rules for identifying WSUs in Chinese, Japanese and Korean .......................................... 6

5.1 Words ...................................................................................................................................................... 6

5.2 Derivationally formed words ................................................................................................................ 6

5.3 Word compounds .................................................................................................................................. 7

5.4 Phrasal compounds .............................................................................................................................. 8

5.5 Idioms ..................................................................................................................................................... 8

5.6 Fixed expressions ................................................................................................................................. 9

5.7 Abbreviations ....................................................................................................................................... 10

5.8 Transliterated loanwords .................................................................................................................... 10

5.9 Strings of foreign or special characters ........................................................................................... 11

5.10 Components of a WSU ........................................................................................................................ 11

6 Specific rules for identifying WSUs in Chinese ............................................................................... 12

6.1 Lexical items followed by the suffix儿(r) .......................................................................................... 12

6.2 Lexical items ........................................................................................................................................ 12

6.2.1 Nouns .................................................................................................................................................... 12

6.2.2 Verbs ..................................................................................................................................................... 17

6.2.3 Adjectives ............................................................................................................................................. 20

6.2.4 Pronouns .............................................................................................................................................. 22

6.2.5 Numerals .............................................................................................................................................. 23

6.2.6 Measure words .................................................................................................................................... 25

6.2.7 Adverbs ................................................................................................................................................ 25

6.2.8 Prepositions ......................................................................................................................................... 26

6.2.9 Conjunctions ........................................................................................................................................ 26

6.2.10 Auxiliary words .................................................................................................................................... 26

6.2.11 Modal words ......................................................................................................................................... 27

6.2.12 Exclamations ....................................................................................................................................... 27

6.2.13 Imitative words .................................................................................................................................... 27

7 Specific rules for identifying WSUs in Japanese text ..................................................................... 27

7.1 Bunsetsus ............................................................................................................................................ 27

7.2 Lexical items ........................................................................................................................................ 27

7.2.1 General rule .......................................................................................................................................... 27

7.2.2 Nouns .................................................................................................................................................... 28

7.2.3 Verbs ..................................................................................................................................................... 32

7.2.4 Adjectives ............................................................................................................................................. 33

7.2.5 Adnouns ............................................................................................................................................... 34

7.2.6 Adverbs ................................................................................................................................................ 34

7.2.7 Conjunctions ........................................................................................................................................ 35

7.2.8 Exclamations ....................................................................................................................................... 35

© ISO 2011 – All rights reserved iii
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SIST ISO 24614-2:2014
ISO 24614-2:2011(E)

7.2.9 Particles ................................................................................................................................................35

7.2.10 Auxiliary verbs .....................................................................................................................................35

8 Specific rules for identifying WSUs in Korean text ..........................................................................36

8.1 Eojeols ..................................................................................................................................................36

8.2 Lexical items ........................................................................................................................................36

8.2.1 General rule ..........................................................................................................................................36

8.2.2 Nouns ....................................................................................................................................................37

8.2.3 Pronouns ..............................................................................................................................................38

8.2.4 Numerals ...............................................................................................................................................39

8.2.5 Verbs .....................................................................................................................................................39

8.2.6 Adjectives .............................................................................................................................................39

8.2.7 Adnouns ...............................................................................................................................................40

8.2.8 Adverbs .................................................................................................................................................40

8.2.9 Exclamations ........................................................................................................................................40

8.3 Grammatical affixes .............................................................................................................................40

Annex A (informative) Comparative table of parts of speech in Chinese, Japanese and Korean ............42

Bibliography ......................................................................................................................................................43

iv © ISO 2011 – All rights reserved
---------------------- Page: 6 ----------------------
SIST ISO 24614-2:2014
ISO 24614-2:2011(E)
Foreword

ISO (the International Organization for Standardization) is a worldwide federation of national standards bodies

(ISO member bodies). The work of preparing International Standards is normally carried out through ISO

technical committees. Each member body interested in a subject for which a technical committee has been

established has the right to be represented on that committee. International organizations, governmental and

non-governmental, in liaison with ISO, also take part in the work. ISO collaborates closely with the

International Electrotechnical Commission (IEC) on all matters of electrotechnical standardization.

International Standards are drafted in accordance with the rules given in the ISO/IEC Directives, Part 2.

The main task of technical committees is to prepare International Standards. Draft International Standards

adopted by the technical committees are circulated to the member bodies for voting. Publication as an

International Standard requires approval by at least 75 % of the member bodies casting a vote.

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent

rights. ISO shall not be held responsible for identifying any or all such patent rights.

ISO 24614-2 was prepared by Technical Committee ISO/TC 37, Terminology and other language and content

resources, Subcommittee SC 4, Language resource management.

ISO 24614 consists of the following parts, under the general title Language resource management — Word

segmentation of written texts:
 Part 1: Basic concepts and general principles
 Part 2: Word segmentation for Chinese, Japanese and Korean
© ISO 2011 – All rights reserved v
---------------------- Page: 7 ----------------------
SIST ISO 24614-2:2014
ISO 24614-2:2011(E)
Introduction

This part of ISO 24614 focuses on word segmentation in Chinese, Japanese and Korean written texts. As far

as typography is concerned, there is no white space between words in Chinese, Japanese or pre-modern

Korean texts. This makes it hard to segment a text into words, unless there is a consistent way of identifying

word segmentation units for those languages. On the other hand, in modern-day Korean text, word forms or

verbal stems that are agglutinated with grammatical affixes, called ‘eojeol’ or ‘malmadi’, are separated by

white space as in English written texts. Hence, it is much easier to identify words or other word segmentation

units in a Korean text. Nevertheless, a large number of words in Korean as well as in Japanese are borrowed

or derived from Chinese words; their internal structures are also based on the word formation principles of

Chinese. As a consequence, general rules for identifying word segmentation units (WSUs) in Chinese,

especially internal WSUs embedded in larger WSUs, are also applicable to some extent to the processing of

Japanese and Korean texts.

The use of characters does not play a real role in identifying WSUs in a text. Many Korean words can be

written either in Chinese or in Korean characters, but the same principles of analysing Chinese-derived words

and identifying sub-WSUs of those words apply. A newspaper published in Beijing is written in simplified

Chinese characters, while a Hong Kong newspaper may be written in traditional Chinese characters. Here

again, the same principles of identifying WSUs apply to both newspapers.

This part of ISO 24614 first sets out the general rules for identifying WSUs in Chinese, Japanese and Korean,

then addresses the specific rules for each language.
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INTERNATIONAL STANDARD ISO 24614-2:2011(E)
Language resource management — Word segmentation of
written texts —
Part 2:
Word segmentation for Chinese, Japanese and Korean
1 Scope

The basic concepts and general principles of word segmentation as defined in ISO 24614-1 apply to Chinese,

Japanese and Korean. Text needs to be segmented into tokens, words, phrases or some other types of

smaller textual units in order to perform certain computational applications on language resources, such as

natural language processing, information retrieval (IR) and machine translation (MT). This part of ISO 24614 is

restricted to the segmentation of a text into words or other word segmentation units (WSUs). This task is

distinct from morphological or syntactic analysis per se, although it greatly depends on morphosyntactic

analysis. It is also different from the task of laying out a framework for constructing a lexicon and identifying its

lexical entries, namely lemmas and lexemes. The frameworks for the latter tasks are provided by ISO 24611,

ISO 24613 and ISO 24615.

The main objective of this part of ISO 24614 is to specify rules for delineating WSUs for Chinese, Japanese

and Korean. Some rules are common to all three languages, though each language also has its own distinct

rules for identifying WSUs. The common features are discussed in Clause 5, then the distinct rules are laid out

in Clause 6 for Chinese, Clause 7 for Japanese and Clause 8 for Korean.
2 Normative references

The following referenced documents are indispensable for the application of this document. For dated

references, only the edition cited applies. For undated references, the latest edition of the referenced

document (including any amendments) applies.
ISO 24611, Language resource management — Morpho-syntactic annotation framework
ISO 24613:2008, Language resource management — Lexical markup framework (LMF)

ISO 24614-1:2010, Language resource management — Word segmentation of written texts — Part 1: Basic

concepts and general principles
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3 Terms and definitions

For the purposes of this document, the terms and definitions given in ISO 24611, ISO 24613 and ISO 24614-1

and the following apply.
3.1
adnoun
ADN
non-conjugating word that modifies a noun
NOTE Adnouns modify nouns, as adverbs modify verbs.
EXAMPLE 1
a. あらゆる 国
arayuru kuni
ADN N
‘every country’
b. 好きな 花
suki+na hana
ADNst+SX N
‘favourite flower’
EXAMPLE 2
a. 새 옷
sae ot
ADN noun
‘new clothes’
b. 빨간 옷
bbalga+n ot
ADJst+GX N
‘red clothes’
3.2
bunsetsu
phrase (3.8) without internal modifying relations

EXAMPLE The sentence 私は学校へ早く行きました(I went to school early) consists of four bunsetsus:

私は(watashiwa), 学校へ (gakkoue), 早く(hayaku) and 行きました(ikimashita) in which
私(watashi) is a pronoun,
は(wa) is a particle,
学校(gakkou) is a noun,
へ(e) is a particle,
早く(hayaku) is an adjective in adverbial usage,
行き(iki) is a verbal stem followed by
まし(mashi) is an auxiliary verb denoting politeness, and
た(ta) is an auxiliary verb indicating the past tense.

NOTE A bunsetsu normally consists of a noun plus its particle(s) or a verb plus its ending(s), auxiliary verb(s) or

particle(s) as shown in the example above.
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3.3
ending
agglutinative affix of a verb or adjective

NOTE Verbs and adjectives end with agglutinative forms, called “endings”. These endings may be a negative form,

an adverbial form, a base form, an adnominal form, an assumption form or an imperative form.

3.4
eojeol
malmaldi

word or its variant word form agglutinated with grammatical affixes

NOTE 1 White space (space between characters) helps to segment text into eojeols.

EXAMPLE
내가 사과를 먹었다
nae+ga sagwa+reul meok+eot+da
pronoun+GX noun+GX Vst+GX+GX
‘I’+SBJ ‘apple’+OBJ ‘eat’+PST+DCL = ‘I ate (an) apple’

NOTE 2 This sentence consists of three eojeols: 내가, 사과를 and 먹었다, each of which is separated by white space.

The acronyms GX, SBJ, OBJ, PST and DCL in the example above stand for grammatical affix, subject, object, past tense

and declarative sentential type, respectively. The pronoun 내 is a variant form of the pronoun 나 referring to the speaker.

먹었다 is an eojeol and at the same time is a word form agglutinated with two grammatical affixes 었 and 다 to a verb

stem .
3.5
lexical item
entry in a lexicon that is a lexeme or one of its variant forms

NOTE Headed by a lemma, each lexical item may be either a free-standing word (or one of its variant word forms) or

a bound (non-free-standing) form such as stems and affixes. See ISO 24614-1:2010 for the definitions of lexeme, lemma

and lexicon.
3.6
measure word

part of speech defining, along with numbers, the quantity of a given object, or identifying

specific objects with demonstrative pronouns such as “this” and “that”

NOTE 1 Whereas English speakers say “one person” or “this person”, Chinese speakers say respectively 一个人(yi ge

ren; numeral + measure word + noun; one person) or 这个人 (zhe ge ren; demonstrative pronoun + measure word +

person; this person), where 个 (ge) is a measure word.

NOTE 2 A set of “verbal measure words” is used to count the number of times an action occurs, rather than the

number of items. For example, in the sentence 我去过三次北京(wo qu guo san ci Beijing; pronoun + verb + auxiliary word

+ numeral + measure word + proper noun; I have been to Beijing three times), the 次(ci) functions as a measure word to

combine with a numeral 三 to derive the adverb三次 (sanci) that modifies the verb 去(qu).

3.7
particle

grammatical affix agglutinated mostly to nominal forms but sometimes to other free-standing

lexical items (3.5)
NOTE The grammatical category particle can be treated as a part of speech.

EXAMPLE The noun phrase 学校へ(gakkoue) is analysed into a noun 学校 (gakkou) and a particle へ(e). The verb

phrase 寒いね(samuine, ‘It is very cold, isn't it?’) is analysed into a verb 寒い (samui) and a particle ね(ne) which

corresponds to the tag ‘isn't it ?’.
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3.8
phrase

group of words that perform a grammatical function and that form a conceptual unit within a sentence

4 Overview
4.1 Introduction

This clause first introduces a markup convention for word segmentation units, then reviews the concept of

word segmentation unit (WSU) which was introduced in ISO 24614-1. Some features shared by Chinese,

Japanese and Korean are discussed in 4.3. A comparative table of parts of speech is given in Annex A.

4.2 Markup convention

The following clauses contain a very large number of examples of WSUs. A simple way of representing WSUs

is introduced here.

NOTE This markup convention is introduced here just for the sake of simple illustration in this part of ISO 24614.

First, a stand-off annotation is adopted; this allows primary data to be kept intact from markup notations.

(More information on linguisitic annotation can be found in ISO 24612.) Exceptions are made concerning this

requirement when primary data in Chinese or some other language are not provided with a romanized version

or when the identification of syllables is not easy.
Second, a citation format consisting of four lines is adopted.
 Line 1 introduces primary text fragment in its original script.
 Line 2 represents annotated fragment in romanized form.
 Line 3 assigns morpho-syntactic descriptions.
 Line 4 provides an English equivalent.

The following symbols are used (optionally) for marking up primary data in a romanized form:

1) the dot ‘.’ for syllable boundaries, if ambiguity arises;
2) the sign ‘+’ (plus) for boundaries between a word and an affix;
3) the underscore ‘_’ for word segmentation units (WSUs);
4) the square brackets ‘[ ]’ for WSUs, if ambiguity arises;
5) the parentheses ‘( )’ for non-WSUs;
6) the symbol ‘:=’ represents combined resultant information.
EXAMPLE
헛돌다
[(heot)+dol]_da
prefix + verbStem_GX := verb
‘in vain’ ‘spin’ := ‘to spin in vain’
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The verb 헛돌다 consists of a prefix 헛 (heot) and a verb 돌다 (dol+da). The verb 돌다 is then analysed into a stem 돌

(dol) and a verbal grammatical affix 다 (da). The example 헛돌다 as a whole is a WSU, while its subpart 돌다 is also a

WSU embedded in it. In Korean, as will be discussed, the prefix 헛 (heot) is not treated as a WSU.

For computational purposes, namely character encoding schemes, the characters in Chinese, Japanese and

Korean are all treated as being syllabic. Hence, each of the characters in primary data can easily be identified

with its corresponding romanized string of alphabetic characters. The word given in the above example, for

instance, consists of three syllable characters: 헛, 돌 and 다, while its corresponding romanized version

‘heotdolda’ also consists of three syllables, ‘heot’, ‘dol’ and ‘da’. As a result, we can identify the first syllable

‘heot’ in the romanized version as corresponding to the first syllable 헛 in the Korean example and also the

following sequence of the two syllables in the romanized version as corresponding to the sequence of two

syllable characters 돌다. This indicates that there is no need to mark up primary data, but to keep them intact

in order to show how they are analysed into WSUs or other morphological units.

In Japanese, however, a single Chinese character may be pronounced as more than one syllable: for example,

the noun consisting of one character桜 is pronounced as a three-syllable string ‘sakura’. In such a case,

primary data are marked up.
4.3 Review of the concept of word segmentation unit

Word segmentation is the process of dividing a text into meaningful units called word segmentation units

(WSUs). Each WSU corresponds to a single concept: for example, ‘the White House’ consists of three words

but designates a single concept referring to the residence of the US President. It follows that ‘the White

House’ corresponds to one WSU. In other words, word count and concept do not necessarily correspond, and

may differ from one language to the next. The single English word ‘pork’ is translated by two words that mean

‘pig meat’ in Chinese 猪肉 (zhu_rou), in Japanese豚肉 (buta_niku), and in Korean 돼지고기 (doeji_gogi). So

although English uses only one word and the other languages use two, in all four languages there is just one

WSU.

A unit that carries a meaning that is useful for any linguistic processing can be defined as a WSU. A WSU can

be an entry in a lexicon or any other type of lexical resource insofar as such an entry is leveraged in some

natural language processing application. In other words, the WSU's dimension is more or less fixed, but

linguistic interferences between compounds inside a WSU are not allowed. Such an extensive, open definition

of WSU is useful for further linguistic processing because some WSUs that frequently occur in corpora are not

systematically decomposable by syntactic or any other linguistic processing.
4.4 Features common to Chinese, Japanese and Korean

Two basic features that are common to Chinese, Japanese and Korean derive from a common cultural

heritage in Far East Asia.

 Firstly, Chinese characters have long been used, and continue to be used, in this part of the world

notwithstanding some differences in their degree of use: Chinese utilizes all of these characters, while

Japanese also uses them in addition to Kana characters. On the other hand, Korean has its own writing

system, but sometimes uses Chinese characters, especially for scholarly purposes in humanities such as

classical studies.

 Secondly, many words and phrases of Chinese origin are used in both Japanese and Korean; they

include 四面楚歌 and 第二次世界大战. Note, however, that the non-simplified or original shapes of

Chinese characters are retained in these languages; in the case of Korean, they may simply be written

using the characters of the Korean writing system. The phrase 四面楚歌 written in Chinese characters, for

instance, is written as사면초가 in Korean.

Because of this historical background, some principles of Chinese word segmentation apply significantly to

Chinese-derived words found in Japanese and Korean. If the word is derived from Chinese characters, the

three languages have common properties. If the word is a noun and consists of two or more Chinese

characters, it will constitute a single WSU as long as the characters are “tightly combined and steadily used” in

accordance with the principles set out in ISO 24614-1; for example, ‘each country’ in English is not a single

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WSU, but two WSUs unlike its Chinese equivalent 各国. However, if the final character is productive in a

limited manner, it forms a single WSU with the preceding word; for example, 東京都 (Tokyo Metropolitan), 8月

(August) and 加速器(accelerator) are single WSUs without being analysed into two WSUs, say 東京 and 都.

Because the motivation for a word segmentation standard is to recommend which WSUs should be listed in a

give
...

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