ISO 24613:2008

Language resource management - Lexical markup framework (LMF)

ISO 24613:2008 describes the Lexical Markup Framework (LMF), a metamodel for representing data in lexical databases used with monolingual and multilingual computer applications. LMF provides mechanisms that allow the development and integration of a variety of electronic lexical resource types. These mechanisms will present existing lexicons as far as possible. If this is impossible, problematic information will be identified and isolated.

Gestion de ressources langagières — Cadre de balisage lexical

Upravljanje z jezikovnimi viri - Ogrodje za označevanje leksikonov (LMF)

Ta mednarodni standard opisuje ogrodje za označevanje leksikonov (LMF), ki je metamodel za predstavitev podatkov v leksikalnih podatkovnih bazah, ki se uporabljajo v enojezičnih in večjezičnih računalniških aplikacijah. LMF zagotavlja mehanizme, ki omogočajo razvoj in integracijo številnih vrst elektronskih leksikalnih virov2). Ti mehanizmi bodo, če je le mogoče, predstavljali obstoječe leksikone. Če je to nemogoče, bodo problematične informacije identificirane in izolirane.

General Information

• Status: Withdrawn
• Publication Date: 16-Nov-2008
• ICS: 01.020 - Terminology (principles and coordination)
• Technical Committee: ISO/TC 37/SC 4 - Language resource management
• Drafting Committee: ISO/TC 37/SC 4 - Language resource management
• Current Stage: 9599 - Withdrawal of International Standard
• Completion Date: 19-Jan-2022
• Ref Project: SIST ISO 24613:2013 - Language resource management - Lexical markup framework (LMF)

Relations

• Revised: ISO 24613-1:2019 - Language resource management — Lexical markup framework (LMF) — Part 1: Core model
• Effective Date: 04-Nov-2015
• Revised: ISO 24613-5:2022 - Language resource management — Lexical markup framework (LMF) — Part 5: Lexical base exchange (LBX) serialization
• Effective Date: 06-Aug-2016
• Revised: ISO 24613-3:2021 - Language resource management — Lexical markup framework (LMF) — Part 3: Etymological extension
• Effective Date: 17-Feb-2018
• Revised: ISO 24613-4:2021 - Language resource management — Lexical markup framework (LMF) — Part 4: TEI serialization
• Effective Date: 17-Feb-2018
• Revised: ISO 24613-2:2020 - Language resource management — Lexical markup framework (LMF) — Part 2: Machine-readable dictionary (MRD) model
• Effective Date: 17-Feb-2018

Standards Content (Sample)

SLOVENSKI STANDARD
SIST ISO 24613:2013
01-julij-2013
8SUDYOMDQMH]MH]LNRYQLPLYLUL2JURGMH]DR]QDþHYDQMHOHNVLNRQRY/0)
Language resource management - Lexical markup framework (LMF)
Gestion de ressources langagières -- Cadre de balisage lexical
Ta slovenski standard je istoveten z: ISO 24613:2008
ICS:
01.020 7HUPLQRORJLMDQDþHODLQ Terminology (principles and
NRRUGLQDFLMD coordination)
SIST ISO 24613:2013 en,fr,de

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

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SIST ISO 24613:2013
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SIST ISO 24613:2013
INTERNATIONAL ISO
STANDARD 24613
First edition
2008-11-15
Language resource management —
Lexical markup framework (LMF)
Gestion de ressources langagières — Cadre de balisage lexical (LMF)
Reference number
ISO 24613:2008(E)
ISO 2008
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SIST ISO 24613:2013
ISO 24613:2008(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

COPYRIGHT PROTECTED DOCUMENT
© ISO 2008

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 [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2008 – All rights reserved
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SIST ISO 24613:2013
ISO 24613:2008(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

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

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

3 Terms and definitions........................................................................................................................... 1

4 Key standards used by LMF ................................................................................................................ 6

4.1 Unicode.................................................................................................................................................. 6

4.2 Language coding .................................................................................................................................. 6

4.3 Script Coding ........................................................................................................................................ 7

4.4 ISO 12620 Data Category Registry (DCR) ..........................................................................................7

4.5 Unified Modeling Language (UML)...................................................................................................... 7

5 The LMF model...................................................................................................................................... 7

5.1 Introduction ........................................................................................................................................... 7

5.2 LMF core package................................................................................................................................. 7

5.3 LMF extension use.............................................................................................................................. 10

5.4 LMF data category selection procedures......................................................................................... 11

5.5 LMF process........................................................................................................................................ 12

Annex A (normative) Morphology extension................................................................................................. 13

Annex B (informative) Morphology examples ............................................................................................... 15

Annex C (normative) Machine readable dictionary extension..................................................................... 21

Annex D (informative) Machine readable dictionary examples ................................................................... 23

Annex E (normative) NLP syntax extension.................................................................................................. 24

Annex F (informative) NLP syntax examples................................................................................................. 26

Annex G (normative) NLP semantics extension ........................................................................................... 29

Annex H (informative) NLP semantic examples............................................................................................ 32

Annex I (normative) NLP multilingual notations extension......................................................................... 39

Annex J (informative) NLP multilingual notations examples....................................................................... 42

Annex K (normative) NLP morphological patterns extension..................................................................... 45

Annex L (informative) NLP morphological patterns examples.................................................................... 49

Annex M (normative) NLP multiword expression patterns extension (MWE)............................................ 63

Annex N (informative) NLP multiword expression patterns example......................................................... 65

Annex O (normative) Constraint expression extension............................................................................... 67

Annex P (informative) Constraint expression example................................................................................ 69

Annex Q (informative) Connection with terminological markup framework (TMF) and other

concept-based representation systems........................................................................................... 71

Annex R (informative) LMF DTD ..................................................................................................................... 72

Bibliography ..................................................................................................................................................... 76

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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 24613 was prepared by Technical Committee ISO/TC 37, Terminology and other language and content

resources, Subcommittee SC 4, Language resource management.

ISO 24613 is designed to coordinate closely with ISO 12620, Terminology and other content and language

resources — Data categories — Specification of data categories and management of a Data Category

Registry for language resources , and ISO 16642, Computer applications in terminology — Terminological

markup framework.
1) To be published. (Revision of ISO 12620:1999)
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Introduction

Optimizing the production, maintenance and extension of electronic lexical resources is one of the crucial

aspects impacting human language technologies (HLT) in general and natural language processing (NLP) in

particular, as well as human-oriented translation technologies. A second crucial aspect involves optimizing the

process leading to their integration in applications. Lexical Markup Framework (LMF) is an abstract

metamodel that provides a common, standardized framework for the construction of computational lexicons.

LMF ensures the encoding of linguistic information in a way that enables reusability in different applications

and for different tasks. LMF provides a common, shared representation of lexical objects, including

morphological, syntactic and semantic aspects.

The goals of LMF are to provide a common model for the creation and use of electronic lexical resources

ranging from small to large in scale, to manage the exchange of data between and among these resources,

and to facilitate the merging of large numbers of different individual electronic resources to form extensive

global electronic resources. The ultimate goal of LMF is to create a modular structure that will facilitate true

content interoperability across all aspects of electronic lexical resources.

The LMF core package describes the basic hierarchy of information of a lexical entry, including information on

the form. The core package is supplemented by various resources that are part of the definition of LMF. These

resources include:

⎯ specific data categories used by the variety of resource types associated with LMF, both those data

categories relevant to the metamodel itself, and those associated with the extensions to the core

package;

⎯ the constraints governing the relationship of these data categories to the metamodel and to its

extensions;

⎯ standard procedures for expressing these categories and thus for anchoring them on the structural

skeleton of LMF and relating them to the respective extension models;

⎯ the vocabularies used by LMF to express related informational objects for describing how to extend LMF

through linkage to a variety of specific resources (extensions) and methods for analysing and designing

such linked systems.

Extensions of the core package which are documented in the annexes of this International Standard include:

a) machine readable dictionaries;
b) natural language processing lexical resources.

LMF extensions are expressed in a framework that describes the reuse of the LMF core components (such as

structures, data categories, and vocabularies) in conjunction with the additional components required for a

specific resource.

Types of individual instantiations of LMF can include such electronic lexical resources as fairly simple lexical

databases, NLP and machine-translation lexicons, as well as electronic monolingual, bilingual and multilingual

lexical databases. LMF provides general structures and mechanisms for analysing and designing new

electronic lexical resources, but LMF does not specify the structures, data constraints and vocabularies to be

used in the design of specific electronic lexical resources. LMF also provides mechanisms for analysing and

describing existing resources using a common descriptive framework. For the purpose of both designing new

lexical resources and describing existing lexical resources, LMF defines the conditions that allow the data

expressed in any one lexical resource to be mapped to the LMF framework, and thus provides an intermediate

format for lexical data exchange.
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SIST ISO 24613:2013
INTERNATIONAL STANDARD ISO 24613:2008(E)
Language resource management — Lexical markup
framework (LMF)
1 Scope

This International Standard describes the Lexical Markup Framework (LMF), a metamodel for representing

data in lexical databases used with monolingual and multilingual computer applications.

LMF provides mechanisms that allow the development and integration of a variety of electronic lexical

resource types . These mechanisms will present existing lexicons as far as possible. If this is impossible,

problematic information will be identified and isolated.
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 639 (all parts), Codes for the representation of names of languages
ISO 1087-1, Terminology work — Vocabulary — Part 1: Theory and application
ISO 1087-2, Terminology work — Vocabulary — Part 2: Computer applications

ISO 12620, Terminology and other content and language resources — Data categories — Specification of

data categories and management of a Data Category Registry for language resources

ISO 15924, Information and documentation — Code for the representation of names of scripts

3 Terms and definitions

For the purposes of this International Standard, the terms and definitions given in ISO 1087-1, ISO 1087-2

and the following apply .
3.1
abbreviated form

form (3.14) resulting from the omission of any part of the full form (3.16) of the same lexeme (3.25)

[9]

2) LMF supports existing lexical resource models such as the Genelex , the EAGLES International Standards for

[5] [6]
Language Engineering (ISLE) and Multilingual ISLE Lexical Entry (MILE) models .
3) To be published. (Revision of ISO 12620:1999)

4) It is worth noting that we have purposely avoided defining and using highly controversial terms such as “word”,

“morpheme”, “base”, “fusion”, “ergative”, “paradigm”, and “collocation”.
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3.2
adjunct

non-essential element associated with a verb as opposed to syntactic arguments (3.43)

EXAMPLE Alfred (syntactic argument) reads a book (syntactic argument) today (adjunct).

NOTE Adverbs are possible adjuncts for a sentence.
3.3
affix

bound morph (3.8) that may contribute to a form (3.14) and participates in the process of inflection (3.20),

agglutination (3.5), derivation (3.12) or composition (3.9)

NOTE Affixes function as prefixes (pre-positioned), suffixes (post-positioned), infixes (inserted) and circumfixes

(combination of prefix and suffix).
3.4
affixation
process in which an affix (3.3) is added to a lemma (3.24) or a stem (3.40)
3.5
agglutination
process in which an agglutinated form (3.6) is made up
3.6
agglutinated form

word form (3.47) that a lexeme (3.25) can take when used in a sentence or a phrase within an agglutinating

language (3.7)
3.7
agglutinating language

language where the different word forms (3.47) of the same lexeme (3.25) exhibit a variation and that may

consist of more than one morph (3.31) but the boundaries between morphs are always clear-cut

[16]
EXAMPLE Korean, Japanese, Hungarian and Turkish are agglutinating languages .
3.8
bound morph
morph that appears only together with one or several other morphs (3.31)
3.9
composition
compounding

lexeme (3.25) formation in which a new lexeme [associated with its part of speech (3.37) information] is

formed by adjoining at least two lexemes, in their original forms (3.14) or with slight transformations

NOTE Composition should not be confused with agglutination and derivation, where bound morphs are added to free

ones.
3.10
compound

lexeme (3.25) associated with part of speech (3.37) information that is built from two or more lexemes

3.11
compound form
form (3.14) resulting from a composition (3.9)
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3.12
derivation

change in the forms (3.14) of a lexeme (3.25) to create a new lexeme, usually by modifying the stem (3.40)

or by affixation (3.4)

NOTE Sometimes derivation signals a change in part of speech, such as nation to nationalize. Sometimes the part of

speech remains the same as in nationalization vs. denationalization.
3.13
derived form
form (3.14) resulting from a derivation (3.12)
3.14
form
sequence of morphs (3.31)
3.15
free morph
morph (3.31) that may stand by itself
EXAMPLE The English noun boy.
3.16
full form

complete representation of a lexeme (3.25) for which there is an abbreviated form (3.6)

3.17
grammatical feature

property associated to the inflected (3.19), agglutinated (3.6), compound (3.11) or derived form (3.13) that

describes the grammatical attribute of the form

NOTE An example of a grammatical feature is: /grammatical gender/. (Following the convention adopted in the

revision of ISO 12620, the slashes are used in order to delimit data category values.)

3.18
graph

minimal unit in a written language including letters, pictograms, ideograms, numerals and punctuations

3.19
inflected form

word form (3.47) that a lexeme (3.25) can take when used in a sentence or a phrase within an inflectional

language (3.21)
3.20
inflection
process in which an inflected form (3.19) is made up
3.21
inflectional language
inflecting language

language where the different word forms (3.47) of the same lexeme (3.25) exhibit a variation and where

there is no clear-cut boundary between morphs (3.31) in that morphs are generally fused together to yield a

single, non-segmentable form (3.14)
[16]
EXAMPLE Spanish, Italian, French and English are inflectional languages .
3.22
interlingua

abstract intermediary language used in the machine translation of human languages

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3.23
isolating language
language where the vast majority of morphs (3.31) are free morphs (3.15)
EXAMPLE Chinese is an isolating language.
3.24
lemma
lemmatized form
canonical form
conventional form (3.14) chosen to represent a lexeme (3.25)

EXAMPLE In European languages, the lemma is usually the /singular/ if there is a variation in /number/, the

/masculine/ form if there is a variation in /gender/ and the /infinitive/ for all verbs. In some languages, certain nouns are

defective in the singular form, in which case, the /plural/ is chosen. In Arabic, for a verb, the lemma is usually considered

as being the third person singular with the accomplished aspect.
3.25
lexeme

abstract unit generally associated with a set of forms (3.14) sharing a common meaning

3.26
lexical entry

container for managing one or several forms (3.14) and possibly one or several meanings in order to describe

a lexeme (3.25)
3.27
lexical resource
lexical database
database consisting of one or several lexicons (3.28)
3.28
lexicon
resource comprising lexical entries (3.26) for a given language

NOTE A special language lexicon or a lexicon prepared for a specific NLP application can comprise a specific subset

of language.
3.29
machine readable dictionary
MRD
electronic lexical resource (3.27) designed to be consulted by human beings

NOTE Historically, MRDs were first computer representations of “printed” dictionaries, that's why they are called

machine readable now.
3.30
machine translation lexicon

electronic lexical resource (3.27) in which the individual lexical entries (3.26) contain equivalents in two or

more languages together with morphological, syntactic and/or semantic information to facilitate automatic or

semi-automatic processing of lexemes (3.25) during machine translation
3.31
morph
sequence of graphs (3.18) or sequence of phones (3.38)
EXAMPLE The word boys consists of two morphs: boy and s.
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3.32
morphological pattern

set of associations and/or operations that build the various forms of a lexeme (3.25), possibly by

inflection (3.20), agglutination (3.5), composition (3.9) or derivation (3.12), depending on the language

NOTE A morphological pattern is not the explicit list of inflected forms. It usually references a prototypical class of

inflectional forms, e.g. ring, as per sing.
3.33
morphology
description of the structure and formation of forms (3.14)
3.34
multiword expression
MWE

lexeme (3.25) made up of a sequence of two or more lexemes that has properties that are not predictable

from the properties of the individual lexemes or their normal mode of combination

NOTE An MWE can be a compound, a fragment of a sentence, or a sentence. The group of lexemes making up an

MWE can be continuous or discontinuous. It is not always possible to mark an MWE with a part of speech.

EXAMPLE “To kick the bucket”, which means to die rather than to hit a bucket with one's foot.

3.35
natural language processing
NLP

field covering knowledge and techniques involved in the processing of linguistic data by a computer

3.36
orthography

way of spelling or writing lexemes (3.25) that conforms to a conventionalized use

NOTE Aside from standardized spellings of alphabetical languages, such as standard UK or US English, or reformed

German spelling, there can be variations such as transliterations of languages in non-native scripts, stenographic

renderings, or representations in the International Phonetic Alphabet. In this regard, orthographic information in a lexical

entry can describe a kind of transformation applied to the form that is the object of the entry.

3.37
part of speech
lexical category
word class
category assigned to a lexeme (3.25) based on its grammatical properties

NOTE Typical parts of speech for European languages include: noun, verb, adjective, adverb, preposition, etc.

3.38
phone
minimal unit in the sound system of a language
3.39
script

set of graphic characters used for the written form (3.14) of one or more languages

[ISO/IEC 10646:2003, definition 4.37]

NOTE The description of scripts ranges from a high level classification such as hieroglyphic or syllabic writing

systems vs. alphabets to a more precise classification like Roman vs. Cyrillic. Scripts are defined by a list of values taken

from ISO 15924.
EXAMPLE Hiragana, Katakana, Latin and Cyrillic.
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3.40
stem

sequence of morphs (3.31) that is smaller than or equal to the form (3.14) of a single lexeme (3.25) and that

may be affected by an inflectional (3.20), agglutinative (3.5), compositional (3.9) or derivation (3.12)

process
3.41
subcategorization frame
valence
valency

set of restrictions on a lexeme (3.25) indicating the properties of the syntactic arguments (3.43) that can or

must occur with this given lexeme
3.42
support verb

verb that makes a generic semantic contribution to the context and that combines with a noun to form a

lexeme (3.25)

EXAMPLE take an exam or give an exam. In these examples, take and give have only limited inherent meaning

based on their semantics, but rather are used in a conventional, generic way to express a collocational conceptualization.

3.43
syntactic argument

one of the essential and functional elements in a clause that identifies the participants in the process referred

to by a verb

EXAMPLE Alfred (syntactic argument) reads a book (syntactic argument) today (adjunct).

3.44
transcription

form (3.14) resulting from a coherent method of writing down speech sounds, to include converting speech

sounds described in one writing system to an equivalent representation of the same speech sounds described

in another writing system
3.45
transliteration

form (3.14) resulting from the conversion of one writing system into another, usually through a one to one

correspondence between characters
3.46
variant
one of the alternative forms (3.14) of a lexeme (3.25)
3.47
word form
form (3.14) that a lexeme (3.25) takes when used in a sentence or a phrase
4 Key standards used by LMF
4.1 Unicode

LMF is Unicode compliant and presumes that all data are represented using Unicode character encodings.

4.2 Language coding

Language identifiers used in LMF-compliant resources shall conform to criteria specified in the ISO 639 family

of standards. Some issues involving the combination of language and country codes, as well as the

coordination of different parts of ISO 639 have been addressed in external standards supported by the

6 © ISO 2008 – All rights reserved
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technology community. It is recommended that users consult the current edition of IETF Best Common

Practices (BCP) 47, Tags for the Identification of Languages in order to resolve issues involving choosing and

[1]
matching identifiers for use in electronic environments .
4.3 Script Coding

When the script code is not part of the language identifier, script identifiers shall conform to criteria specified in

ISO 15924.
4.4 ISO 12620 Data Category Registry (DCR)

The designers of an LMF conformant lexicon shall use data categories from the ISO 12620 Data Category

Registry (DCR) located at www.isocat.org.
4.5 Unified Modeling Language (UML)

LMF complies with the specifications and modeling principles of UML as defined by the Object Management

[2]

Group (OMG) . LMF uses a subset of UML that is relevant for linguistic description.

5 The LMF model
5.1 Introduction

LMF models are represented by UML classes, associations among the classes, and a set of ISO 12620 data

categories that function as UML attribute-value pairs. The data categories are used to adorn the UML

diagrams that provide a high level view of the model. LMF specifications in the form of textual descriptions that

describe the semantics of the modeling elements provide more complete information about classes,

relationships, and extensions than can be included in UML diagrams.

In this process, lexicon developers shall use the classes that are specified in the LMF core package (5.2).

Additionally, developers can optionally use classes that are defined in the LMF extensions (see relevant

annexes). Developers shall define a data category selection (DCS) as specified for LMF data category

selection procedures (5.4).
5.2 LMF core package

The LMF core package is a metamodel that provides a flexible basis for building LMF models and extensions,

see Figure 1.
5.2.1 Lexical Resource class

Lexical Resource is a class representing the entire resource. Lexical Resource occurs once and only once.

The Lexical Resource instance is a container for one or more lexicons.
5.2.2 Global Information class

Global Information is a class representing administrative information and other general attributes. There is an

aggregation relationship between the Lexical Resource class and the Global Information class in that the latter

describes the administrative information and general attributes of the entire resource. The Global Information

class does not allow subclasses.
The Global Information instance must contain at least the following attribute:

⎯ /language coding/ This attribute specifies which standard is used in order to code the language

names within the whole Lexical Resource instance.
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The Global Information instance may contain the following at
...

INTERNATIONAL ISO
STANDARD 24613
First edition
2008-11-15
Language resource management —
Lexical markup framework (LMF)
Gestion de ressources langagières — Cadre de balisage lexical (LMF)
Reference number
ISO 24613:2008(E)
ISO 2008
---------------------- Page: 1 ----------------------
ISO 24613:2008(E)
PDF disclaimer

This PDF file may contain embedded typefaces. In accordance with Adobe's licensing policy, this file may be printed or viewed but

shall not be edited unless the typefaces which are embedded are licensed to and installed on the computer performing the editing. In

downloading this file, parties accept therein the responsibility of not infringing Adobe's licensing policy. The ISO Central Secretariat

accepts no liability in this area.
Adobe is a trademark of Adobe Systems Incorporated.

Details of the software products used to create this PDF file can be found in the General Info relative to the file; the PDF-creation

parameters were optimized for printing. Every care has been taken to ensure that the file is suitable for use by ISO member bodies. In

the unlikely event that a problem relating to it is found, please inform the Central Secretariat at the address given below.

COPYRIGHT PROTECTED DOCUMENT
© ISO 2008

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 [e-mail]
Web www.iso.org
Published in Switzerland
ii © ISO 2008 – All rights reserved
---------------------- Page: 2 ----------------------
ISO 24613:2008(E)
Contents Page

Foreword............................................................................................................................................................ iv

Introduction ........................................................................................................................................................ v

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

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

3 Terms and definitions........................................................................................................................... 1

4 Key standards used by LMF ................................................................................................................ 6

4.1 Unicode.................................................................................................................................................. 6

4.2 Language coding .................................................................................................................................. 6

4.3 Script Coding ........................................................................................................................................ 7

4.4 ISO 12620 Data Category Registry (DCR) ..........................................................................................7

4.5 Unified Modeling Language (UML)...................................................................................................... 7

5 The LMF model...................................................................................................................................... 7

5.1 Introduction ........................................................................................................................................... 7

5.2 LMF core package................................................................................................................................. 7

5.3 LMF extension use.............................................................................................................................. 10

5.4 LMF data category selection procedures......................................................................................... 11

5.5 LMF process........................................................................................................................................ 12

Annex A (normative) Morphology extension................................................................................................. 13

Annex B (informative) Morphology examples ............................................................................................... 15

Annex C (normative) Machine readable dictionary extension..................................................................... 21

Annex D (informative) Machine readable dictionary examples ................................................................... 23

Annex E (normative) NLP syntax extension.................................................................................................. 24

Annex F (informative) NLP syntax examples................................................................................................. 26

Annex G (normative) NLP semantics extension ........................................................................................... 29

Annex H (informative) NLP semantic examples............................................................................................ 32

Annex I (normative) NLP multilingual notations extension......................................................................... 39

Annex J (informative) NLP multilingual notations examples....................................................................... 42

Annex K (normative) NLP morphological patterns extension..................................................................... 45

Annex L (informative) NLP morphological patterns examples.................................................................... 49

Annex M (normative) NLP multiword expression patterns extension (MWE)............................................ 63

Annex N (informative) NLP multiword expression patterns example......................................................... 65

Annex O (normative) Constraint expression extension............................................................................... 67

Annex P (informative) Constraint expression example................................................................................ 69

Annex Q (informative) Connection with terminological markup framework (TMF) and other

concept-based representation systems........................................................................................... 71

Annex R (informative) LMF DTD ..................................................................................................................... 72

Bibliography ..................................................................................................................................................... 76

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ISO 24613:2008(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 24613 was prepared by Technical Committee ISO/TC 37, Terminology and other language and content

resources, Subcommittee SC 4, Language resource management.

ISO 24613 is designed to coordinate closely with ISO 12620, Terminology and other content and language

resources — Data categories — Specification of data categories and management of a Data Category

Registry for language resources , and ISO 16642, Computer applications in terminology — Terminological

markup framework.
1) To be published. (Revision of ISO 12620:1999)
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ISO 24613:2008(E)
Introduction

Optimizing the production, maintenance and extension of electronic lexical resources is one of the crucial

aspects impacting human language technologies (HLT) in general and natural language processing (NLP) in

particular, as well as human-oriented translation technologies. A second crucial aspect involves optimizing the

process leading to their integration in applications. Lexical Markup Framework (LMF) is an abstract

metamodel that provides a common, standardized framework for the construction of computational lexicons.

LMF ensures the encoding of linguistic information in a way that enables reusability in different applications

and for different tasks. LMF provides a common, shared representation of lexical objects, including

morphological, syntactic and semantic aspects.

The goals of LMF are to provide a common model for the creation and use of electronic lexical resources

ranging from small to large in scale, to manage the exchange of data between and among these resources,

and to facilitate the merging of large numbers of different individual electronic resources to form extensive

global electronic resources. The ultimate goal of LMF is to create a modular structure that will facilitate true

content interoperability across all aspects of electronic lexical resources.

The LMF core package describes the basic hierarchy of information of a lexical entry, including information on

the form. The core package is supplemented by various resources that are part of the definition of LMF. These

resources include:

⎯ specific data categories used by the variety of resource types associated with LMF, both those data

categories relevant to the metamodel itself, and those associated with the extensions to the core

package;

⎯ the constraints governing the relationship of these data categories to the metamodel and to its

extensions;

⎯ standard procedures for expressing these categories and thus for anchoring them on the structural

skeleton of LMF and relating them to the respective extension models;

⎯ the vocabularies used by LMF to express related informational objects for describing how to extend LMF

through linkage to a variety of specific resources (extensions) and methods for analysing and designing

such linked systems.

Extensions of the core package which are documented in the annexes of this International Standard include:

a) machine readable dictionaries;
b) natural language processing lexical resources.

LMF extensions are expressed in a framework that describes the reuse of the LMF core components (such as

structures, data categories, and vocabularies) in conjunction with the additional components required for a

specific resource.

Types of individual instantiations of LMF can include such electronic lexical resources as fairly simple lexical

databases, NLP and machine-translation lexicons, as well as electronic monolingual, bilingual and multilingual

lexical databases. LMF provides general structures and mechanisms for analysing and designing new

electronic lexical resources, but LMF does not specify the structures, data constraints and vocabularies to be

used in the design of specific electronic lexical resources. LMF also provides mechanisms for analysing and

describing existing resources using a common descriptive framework. For the purpose of both designing new

lexical resources and describing existing lexical resources, LMF defines the conditions that allow the data

expressed in any one lexical resource to be mapped to the LMF framework, and thus provides an intermediate

format for lexical data exchange.
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INTERNATIONAL STANDARD ISO 24613:2008(E)
Language resource management — Lexical markup
framework (LMF)
1 Scope

This International Standard describes the Lexical Markup Framework (LMF), a metamodel for representing

data in lexical databases used with monolingual and multilingual computer applications.

LMF provides mechanisms that allow the development and integration of a variety of electronic lexical

resource types . These mechanisms will present existing lexicons as far as possible. If this is impossible,

problematic information will be identified and isolated.
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 639 (all parts), Codes for the representation of names of languages
ISO 1087-1, Terminology work — Vocabulary — Part 1: Theory and application
ISO 1087-2, Terminology work — Vocabulary — Part 2: Computer applications

ISO 12620, Terminology and other content and language resources — Data categories — Specification of

data categories and management of a Data Category Registry for language resources

ISO 15924, Information and documentation — Code for the representation of names of scripts

3 Terms and definitions

For the purposes of this International Standard, the terms and definitions given in ISO 1087-1, ISO 1087-2

and the following apply .
3.1
abbreviated form

form (3.14) resulting from the omission of any part of the full form (3.16) of the same lexeme (3.25)

[9]

2) LMF supports existing lexical resource models such as the Genelex , the EAGLES International Standards for

[5] [6]
Language Engineering (ISLE) and Multilingual ISLE Lexical Entry (MILE) models .
3) To be published. (Revision of ISO 12620:1999)

4) It is worth noting that we have purposely avoided defining and using highly controversial terms such as “word”,

“morpheme”, “base”, “fusion”, “ergative”, “paradigm”, and “collocation”.
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ISO 24613:2008(E)
3.2
adjunct

non-essential element associated with a verb as opposed to syntactic arguments (3.43)

EXAMPLE Alfred (syntactic argument) reads a book (syntactic argument) today (adjunct).

NOTE Adverbs are possible adjuncts for a sentence.
3.3
affix

bound morph (3.8) that may contribute to a form (3.14) and participates in the process of inflection (3.20),

agglutination (3.5), derivation (3.12) or composition (3.9)

NOTE Affixes function as prefixes (pre-positioned), suffixes (post-positioned), infixes (inserted) and circumfixes

(combination of prefix and suffix).
3.4
affixation
process in which an affix (3.3) is added to a lemma (3.24) or a stem (3.40)
3.5
agglutination
process in which an agglutinated form (3.6) is made up
3.6
agglutinated form

word form (3.47) that a lexeme (3.25) can take when used in a sentence or a phrase within an agglutinating

language (3.7)
3.7
agglutinating language

language where the different word forms (3.47) of the same lexeme (3.25) exhibit a variation and that may

consist of more than one morph (3.31) but the boundaries between morphs are always clear-cut

[16]
EXAMPLE Korean, Japanese, Hungarian and Turkish are agglutinating languages .
3.8
bound morph
morph that appears only together with one or several other morphs (3.31)
3.9
composition
compounding

lexeme (3.25) formation in which a new lexeme [associated with its part of speech (3.37) information] is

formed by adjoining at least two lexemes, in their original forms (3.14) or with slight transformations

NOTE Composition should not be confused with agglutination and derivation, where bound morphs are added to free

ones.
3.10
compound

lexeme (3.25) associated with part of speech (3.37) information that is built from two or more lexemes

3.11
compound form
form (3.14) resulting from a composition (3.9)
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3.12
derivation

change in the forms (3.14) of a lexeme (3.25) to create a new lexeme, usually by modifying the stem (3.40)

or by affixation (3.4)

NOTE Sometimes derivation signals a change in part of speech, such as nation to nationalize. Sometimes the part of

speech remains the same as in nationalization vs. denationalization.
3.13
derived form
form (3.14) resulting from a derivation (3.12)
3.14
form
sequence of morphs (3.31)
3.15
free morph
morph (3.31) that may stand by itself
EXAMPLE The English noun boy.
3.16
full form

complete representation of a lexeme (3.25) for which there is an abbreviated form (3.6)

3.17
grammatical feature

property associated to the inflected (3.19), agglutinated (3.6), compound (3.11) or derived form (3.13) that

describes the grammatical attribute of the form

NOTE An example of a grammatical feature is: /grammatical gender/. (Following the convention adopted in the

revision of ISO 12620, the slashes are used in order to delimit data category values.)

3.18
graph

minimal unit in a written language including letters, pictograms, ideograms, numerals and punctuations

3.19
inflected form

word form (3.47) that a lexeme (3.25) can take when used in a sentence or a phrase within an inflectional

language (3.21)
3.20
inflection
process in which an inflected form (3.19) is made up
3.21
inflectional language
inflecting language

language where the different word forms (3.47) of the same lexeme (3.25) exhibit a variation and where

there is no clear-cut boundary between morphs (3.31) in that morphs are generally fused together to yield a

single, non-segmentable form (3.14)
[16]
EXAMPLE Spanish, Italian, French and English are inflectional languages .
3.22
interlingua

abstract intermediary language used in the machine translation of human languages

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ISO 24613:2008(E)
3.23
isolating language
language where the vast majority of morphs (3.31) are free morphs (3.15)
EXAMPLE Chinese is an isolating language.
3.24
lemma
lemmatized form
canonical form
conventional form (3.14) chosen to represent a lexeme (3.25)

EXAMPLE In European languages, the lemma is usually the /singular/ if there is a variation in /number/, the

/masculine/ form if there is a variation in /gender/ and the /infinitive/ for all verbs. In some languages, certain nouns are

defective in the singular form, in which case, the /plural/ is chosen. In Arabic, for a verb, the lemma is usually considered

as being the third person singular with the accomplished aspect.
3.25
lexeme

abstract unit generally associated with a set of forms (3.14) sharing a common meaning

3.26
lexical entry

container for managing one or several forms (3.14) and possibly one or several meanings in order to describe

a lexeme (3.25)
3.27
lexical resource
lexical database
database consisting of one or several lexicons (3.28)
3.28
lexicon
resource comprising lexical entries (3.26) for a given language

NOTE A special language lexicon or a lexicon prepared for a specific NLP application can comprise a specific subset

of language.
3.29
machine readable dictionary
MRD
electronic lexical resource (3.27) designed to be consulted by human beings

NOTE Historically, MRDs were first computer representations of “printed” dictionaries, that's why they are called

machine readable now.
3.30
machine translation lexicon

electronic lexical resource (3.27) in which the individual lexical entries (3.26) contain equivalents in two or

more languages together with morphological, syntactic and/or semantic information to facilitate automatic or

semi-automatic processing of lexemes (3.25) during machine translation
3.31
morph
sequence of graphs (3.18) or sequence of phones (3.38)
EXAMPLE The word boys consists of two morphs: boy and s.
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3.32
morphological pattern

set of associations and/or operations that build the various forms of a lexeme (3.25), possibly by

inflection (3.20), agglutination (3.5), composition (3.9) or derivation (3.12), depending on the language

NOTE A morphological pattern is not the explicit list of inflected forms. It usually references a prototypical class of

inflectional forms, e.g. ring, as per sing.
3.33
morphology
description of the structure and formation of forms (3.14)
3.34
multiword expression
MWE

lexeme (3.25) made up of a sequence of two or more lexemes that has properties that are not predictable

from the properties of the individual lexemes or their normal mode of combination

NOTE An MWE can be a compound, a fragment of a sentence, or a sentence. The group of lexemes making up an

MWE can be continuous or discontinuous. It is not always possible to mark an MWE with a part of speech.

EXAMPLE “To kick the bucket”, which means to die rather than to hit a bucket with one's foot.

3.35
natural language processing
NLP

field covering knowledge and techniques involved in the processing of linguistic data by a computer

3.36
orthography

way of spelling or writing lexemes (3.25) that conforms to a conventionalized use

NOTE Aside from standardized spellings of alphabetical languages, such as standard UK or US English, or reformed

German spelling, there can be variations such as transliterations of languages in non-native scripts, stenographic

renderings, or representations in the International Phonetic Alphabet. In this regard, orthographic information in a lexical

entry can describe a kind of transformation applied to the form that is the object of the entry.

3.37
part of speech
lexical category
word class
category assigned to a lexeme (3.25) based on its grammatical properties

NOTE Typical parts of speech for European languages include: noun, verb, adjective, adverb, preposition, etc.

3.38
phone
minimal unit in the sound system of a language
3.39
script

set of graphic characters used for the written form (3.14) of one or more languages

[ISO/IEC 10646:2003, definition 4.37]

NOTE The description of scripts ranges from a high level classification such as hieroglyphic or syllabic writing

systems vs. alphabets to a more precise classification like Roman vs. Cyrillic. Scripts are defined by a list of values taken

from ISO 15924.
EXAMPLE Hiragana, Katakana, Latin and Cyrillic.
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ISO 24613:2008(E)
3.40
stem

sequence of morphs (3.31) that is smaller than or equal to the form (3.14) of a single lexeme (3.25) and that

may be affected by an inflectional (3.20), agglutinative (3.5), compositional (3.9) or derivation (3.12)

process
3.41
subcategorization frame
valence
valency

set of restrictions on a lexeme (3.25) indicating the properties of the syntactic arguments (3.43) that can or

must occur with this given lexeme
3.42
support verb

verb that makes a generic semantic contribution to the context and that combines with a noun to form a

lexeme (3.25)

EXAMPLE take an exam or give an exam. In these examples, take and give have only limited inherent meaning

based on their semantics, but rather are used in a conventional, generic way to express a collocational conceptualization.

3.43
syntactic argument

one of the essential and functional elements in a clause that identifies the participants in the process referred

to by a verb

EXAMPLE Alfred (syntactic argument) reads a book (syntactic argument) today (adjunct).

3.44
transcription

form (3.14) resulting from a coherent method of writing down speech sounds, to include converting speech

sounds described in one writing system to an equivalent representation of the same speech sounds described

in another writing system
3.45
transliteration

form (3.14) resulting from the conversion of one writing system into another, usually through a one to one

correspondence between characters
3.46
variant
one of the alternative forms (3.14) of a lexeme (3.25)
3.47
word form
form (3.14) that a lexeme (3.25) takes when used in a sentence or a phrase
4 Key standards used by LMF
4.1 Unicode

LMF is Unicode compliant and presumes that all data are represented using Unicode character encodings.

4.2 Language coding

Language identifiers used in LMF-compliant resources shall conform to criteria specified in the ISO 639 family

of standards. Some issues involving the combination of language and country codes, as well as the

coordination of different parts of ISO 639 have been addressed in external standards supported by the

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ISO 24613:2008(E)

technology community. It is recommended that users consult the current edition of IETF Best Common

Practices (BCP) 47, Tags for the Identification of Languages in order to resolve issues involving choosing and

[1]
matching identifiers for use in electronic environments .
4.3 Script Coding

When the script code is not part of the language identifier, script identifiers shall conform to criteria specified in

ISO 15924.
4.4 ISO 12620 Data Category Registry (DCR)

The designers of an LMF conformant lexicon shall use data categories from the ISO 12620 Data Category

Registry (DCR) located at www.isocat.org.
4.5 Unified Modeling Language (UML)

LMF complies with the specifications and modeling principles of UML as defined by the Object Management

[2]

Group (OMG) . LMF uses a subset of UML that is relevant for linguistic description.

5 The LMF model
5.1 Introduction

LMF models are represented by UML classes, associations among the classes, and a set of ISO 12620 data

categories that function as UML attribute-value pairs. The data categories are used to adorn the UML

diagrams that provide a high level view of the model. LMF specifications in the form of textual descriptions that

describe the semantics of the modeling elements provide more complete information about classes,

relationships, and extensions than can be included in UML diagrams.

In this process, lexicon developers shall use the classes that are specified in the LMF core package (5.2).

Additionally, developers can optionally use classes that are defined in the LMF extensions (see relevant

annexes). Developers shall define a data category selection (DCS) as specified for LMF data category

selection procedures (5.4).
5.2 LMF core package

The LMF core package is a metamodel that provides a flexible basis for building LMF models and extensions,

see Figure 1.
5.2.1 Lexical Resource class

Lexical Resource is a class representing the entire resource. Lexical Resource occurs once and only once.

The Lexical Resource instance is a container for one or more lexicons.
5.2.2 Global Information class

Global Information is a class representing administrative information and other general attributes. There is an

aggregation relationship between the Lexical Resource class and the Global Information class in that the latter

describes the administrative information and general attributes of the entire resource. The Global Information

class does not allow subclasses.
The Global Information instance must contain at least the following attribute:

⎯ /language coding/ This attribute specifies which standard is used in order to code the language

names within the whole Lexical Resource instance.
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ISO 24613:2008(E)
The Global Information instance may contain the following attributes:

⎯ /script coding/ This attribute specifies which standard is used in order to code the script names

within the whole Lexical Resource instance;

⎯ /character coding/ This attribute specifies which Unicode version is used within the whole Lexical

Resource instance.

NOTE Other standard related precisions may be specified on the Global Information instance.

Global Information Lexical Resource
1..*
Lexicon
1..*
1..*
Form Lexical Entry
0..*
0..*
0..*
Sense
Form Representation
0..*
Representation
Definition
0..*
0..*
Text Representation
0..*
Statement
Figure 1 — LMF core package
5.2.3 Lexicon class

Lexicon is a class containing all the lexical entries of a given language within the entire resource. A Lexicon

instance must contain at least one lexical entry. The Lexicon class does not allow subclasses.

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ISO 24613:2008(E)
5.2.4 Lexical Entry class
Lexical Entry is a class representing a lexeme in a given language. The
...