ISO 24613-1:2019

Language resource management - Lexical markup framework (LMF) - Part 1: Core model

This document describes the core model of the lexical markup framework (LMF)l, a metamodel for representing data in monolingual and multilingual lexical databases used with computer applications. LMF provides mechanisms that allow the development and integration of a variety of electronic lexical resource types.

Gestion des ressources linguistiques — Cadre de balisage lexical (LMF) — Partie 1: Modèle de base

Upravljanje jezikovnih virov - Ogrodje za označevanje leksikonov (LMF) - 1. del: Jedrni model

Ta dokument opisuje jedrni model ogrodja za označevanje leksikonov (LMF)l, metamodel za predstavljanje podatkov v enojezičnih in večjezičnih leksikalnih zbirkah podatkov, ki se uporabljajo z računalniškimi aplikacijami.
LMF zagotavlja mehanizme, ki omogočajo razvoj in integracijo številnih vrst elektronskih leksikalnih virov.

General Information

• Status: Withdrawn
• Publication Date: 19-Jun-2019
• ICS: 01.020 - Terminology (principles and coordination)
• ICS: 35.240.30 - IT applications in information, documentation and publishing
• Technical Committee: ISO/TC 37/SC 4 - Language resource management
• Drafting Committee: ISO/TC 37/SC 4/WG 4 - Lexical resources
• Current Stage: 9599 - Withdrawal of International Standard
• Start Date: 15-Jan-2024
• Completion Date: 13-Dec-2025
• Ref Project: SIST ISO 24613-1:2019 - Language resource management -- Lexical markup framework (LMF) -- Part 1: Core model

Relations

• Revised: ISO 24613-1:2024 - Language resource management - Lexical markup framework (LMF) - Part 1: Core model
• Effective Date: 06-Jun-2022
• Revises: ISO 24613:2008 - Language resource management - Lexical markup framework (LMF)
• Effective Date: 04-Nov-2015

Standards Content (Sample)

SLOVENSKI STANDARD
01-oktober-2019
Upravljanje jezikovnih virov - Ogrodje za označevanje leksikonov (LMF) - 1. del:
Jedrni model
Language resource management -- Lexical markup framework (LMF) -- Part 1: Core
model
Gestion de ressources linguistiques -- Cadre de balisage lexical -- Partie 1: Modèle de
base
Ta slovenski standard je istoveten z: ISO 24613-1:2019
ICS:
01.020 Terminologija (načela in Terminology (principles and
koordinacija) coordination)
01.140.20 Informacijske vede Information sciences
35.240.30 Uporabniške rešitve IT v IT applications in information,
informatiki, dokumentiranju in documentation and
založništvu publishing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 24613-1
First edition
2019-06
Language resource management —
Lexical markup framework (LMF) —
Part 1:
Core model
Gestion des ressources linguistiques — Cadre de balisage lexical
(LMF) —
Partie 1: Modèle de base
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Key standards used by LMF . 3
4.1 Unicode . 3
4.2 Language coding . 3
4.3 Script coding . 3
4.4 Unified modeling language (UML) . 3
5 The LMF model . 3
5.1 Introduction . 3
5.2 Class inheritance and data category selection procedures . 4
5.2.1 Class inheritance . 4
5.2.2 LMF attributes . . 4
5.2.3 Data category selection (DCS) . 4
5.2.4 User-defined data categories . 4
5.3 LMF core package . 4
5.3.1 General. 4
5.3.2 LexicalResource class . 5
5.3.3 GlobalInformation class . 5
5.3.4 Lexicon class . 6
5.3.5 LexiconInformation class . 6
5.3.6 LexicalEntry class . 6
5.3.7 Form class . 6
5.3.8 OrthographicRepresentation class . 6
5.3.9 GrammaticalInformation Class . 6
5.3.10 Sense class . 7
5.3.11 Definition class . 7
5.4 Cross reference (CrossREF) model . 7
5.4.1 General. 7
5.4.2 CrossREF and CrossREFConstraint classes . 7
5.4.3 CrossREFConstraint class . 7
5.5 Methods for data category selection and subclass creation . 7
5.5.1 General. 7
5.5.2 Generalization (typing) . 8
5.5.3 Object instantiation . 8
5.5.4 Design choices . 8
5.5.5 Data categories for orthographic representation . 9
5.5.6 Principles for model simplification. 9
5.6 LMF extension use . 9
5.6.1 General. 9
5.6.2 Lexicon comparison .10
Annex A (informative) Data category examples .11
Bibliography .13
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso
.org/iso/foreword .html.
The document was prepared by Technical Committee ISO/TC 37, Language and terminology,
Subcommittee 4, Language resource management.
This first edition of ISO 24613-1, together with ISO 24613-2 to ISO 24613-6, cancels and replaces
ISO 24613:2008, which has been technically revised.
The main changes compared to the previous edition are as follows:
The content has been entirely revised and subdivided into parts. Part 1, Core model, contains the
body of the previous edition. New classes include LexiconInformation and GrammaticalInformation.
The Representation class has been renamed the OrthographicRepresentation class. In addition, the
OrthographicRepresentation subclasses, FormRepresentation and TextRepresentation, no longer are
part of the core model, providing it with greater modeling flexibility. The LexicalEntry subclass now
allows subclasses, providing improved extensibility and flexibility for modeling future parts. The
addition of the CrossREF class and associated metadata provides a formal model for cross-reference
design and implementation, closing a functional gap in the previous edition. A thoroughly revised
description of data category allocation mechanisms and their relationship to generalization by typing
provides a more incisive description of how these interdependent mechanisms enable flexible and
extensible designs.
A list of all parts in the ISO 24613 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved

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.
[3]
LMF supports existing lexical resource models such as Genelex , the EAGLES International Standard
[4] [10]
for Language Engineering (ISLE) , Multilingual ISLE Lexical Entry (MILE) models , Text Encoding
[8] [7]
Initiative (TEI) guidelines , Ontolex , and the Language Base Exchange (LBX) serialization together
[5]
with the U.S. Government Wordscape On-Line Dictionary system .
[9]
LMF uses UML modeling processes . The LMF core package describes the basic hierarchy of information
of a lexical entry, including information on the word 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 in additional LMF parts (see Annex A for data category examples);
— 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.
LMF parts 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.
The parts currently in or planned for the new organization of ISO 24613 include Part 1: Core model, Part
2: Machine readable dictionary (MRD) model, Part 3: Diachrony-etymology, Part 4: TEI serialization, Part
5: LBX serialization, and Part 6: Syntax and semantics.
[2]
The ISO 24613 series is designed to coordinate closely with ISO 16642 .
INTERNATIONAL STANDARD ISO 24613-1:2019(E)
Language resource management — Lexical markup
framework (LMF) —
Part 1:
Core model
1 Scope
This document describes the core model of the lexical markup framework (LMF)l, a metamodel for
representing data in monolingual and multilingual lexical databases used with computer applications.
LMF provides mechanisms that allow the development and integration of a variety of electronic lexical
resource types.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 15924, Information and documentation — Codes for the representation of names of scripts
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
data category
DC
elementary descriptor used in a linguistic description or annotation scheme
3.2
word form
instance of a word, multi-word expression, root, stem, or morpheme
3.3
grammatical feature
property associated with a word form (3.2) to describe one of its grammatical attributes
EXAMPLE /grammatical gender/
3.4
lemma
lemmatized form
canonical form
conventional word form (3.2) chosen to represent a lexeme (3.5)
Note 1 to entry: In many European languages, the lemma is usually the /singular/ for a noun 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 sometimes considered as being the third person singular with the accomplished aspect, in
other approaches it is considered as being the root.
3.5
lexeme
abstract unit generally associated with a set of word forms (3.2) sharing a common meaning
[SOURCE: ISO 24613:2008, 3.25, modified – "forms" replaced with "word forms".]
3.6
lexical resource
lexical database
database consisting of one or several lexicons (3.7)
3.7
lexicon
resource comprising lexical entries for one or several languages
Note 1 to entry: A special language lexicon or a lexicon prepared for a specific NLP application can comprise a
specific subset of a language.
3.8
multiword expression
MWE
lexeme (3.5) made up of a sequence of two or more lexemes that has properties that may not be
predictable from the properties of the individual lexemes or their normal mode of combination
EXAMPLE “To kick the bucket”, an idiomatic expression which means to die rather than to hit a bucket with
one's foot. An idiomatic expression is a subtype of MWE whose properties are not predictable from the properties
of the individual lexemes.
Note 1 to entry: 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 (3.13).
3.9
natural language processing
NLP
field covering knowledge and techniques involved in the processing of linguistic data by a computer
3.10
orthography
way of spelling or writing lexemes (3.5) that conforms to a conventionalized use
Note 1 to entry: Usually, the notion of orthography covers standardized spellings of alphabetic languages, such
as standard UK or US English, or reformed German spelling, as well as hieroglyphic or syllabic writing systems.
For the purpose of this standard, we also subsume variations such as transliterations of languages in non-native
scripts, stenographic renderings, or representations in the International Phonetic Alphabet under the notion of
orthography.
2 © ISO 2019 – All rights reserved

3.11
part of speech
lexical category
word class
category assigned to a lexeme (3.5) based on its grammatical properties
EXAMPLE Typical parts of speech f
...

SLOVENSKI STANDARD
01-oktober-2019
Upravljanje jezikovnih virov - Ogrodje za označevanje leksikonov (LMF) - 1. del:
Jedrni model
Language resource management -- Lexical markup framework (LMF) -- Part 1: Core
model
Gestion de ressources linguistiques -- Cadre de balisage lexical -- Partie 1: Modèle de
base
Ta slovenski standard je istoveten z: ISO 24613-1:2019
ICS:
01.140.20 Informacijske vede Information sciences
35.240.30 Uporabniške rešitve IT v IT applications in information,
informatiki, dokumentiranju in documentation and
založništvu publishing
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

INTERNATIONAL ISO
STANDARD 24613-1
First edition
2019-06
Language resource management —
Lexical markup framework (LMF) —
Part 1:
Core model
Gestion des ressources linguistiques — Cadre de balisage lexical
(LMF) —
Partie 1: Modèle de base
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Key standards used by LMF . 3
4.1 Unicode . 3
4.2 Language coding . 3
4.3 Script coding . 3
4.4 Unified modeling language (UML) . 3
5 The LMF model . 3
5.1 Introduction . 3
5.2 Class inheritance and data category selection procedures . 4
5.2.1 Class inheritance . 4
5.2.2 LMF attributes . . 4
5.2.3 Data category selection (DCS) . 4
5.2.4 User-defined data categories . 4
5.3 LMF core package . 4
5.3.1 General. 4
5.3.2 LexicalResource class . 5
5.3.3 GlobalInformation class . 5
5.3.4 Lexicon class . 6
5.3.5 LexiconInformation class . 6
5.3.6 LexicalEntry class . 6
5.3.7 Form class . 6
5.3.8 OrthographicRepresentation class . 6
5.3.9 GrammaticalInformation Class . 6
5.3.10 Sense class . 7
5.3.11 Definition class . 7
5.4 Cross reference (CrossREF) model . 7
5.4.1 General. 7
5.4.2 CrossREF and CrossREFConstraint classes . 7
5.4.3 CrossREFConstraint class . 7
5.5 Methods for data category selection and subclass creation . 7
5.5.1 General. 7
5.5.2 Generalization (typing) . 8
5.5.3 Object instantiation . 8
5.5.4 Design choices . 8
5.5.5 Data categories for orthographic representation . 9
5.5.6 Principles for model simplification. 9
5.6 LMF extension use . 9
5.6.1 General. 9
5.6.2 Lexicon comparison .10
Annex A (informative) Data category examples .11
Bibliography .13
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso
.org/iso/foreword .html.
The document was prepared by Technical Committee ISO/TC 37, Language and terminology,
Subcommittee 4, Language resource management.
This first edition of ISO 24613-1, together with ISO 24613-2 to ISO 24613-6, cancels and replaces
ISO 24613:2008, which has been technically revised.
The main changes compared to the previous edition are as follows:
The content has been entirely revised and subdivided into parts. Part 1, Core model, contains the
body of the previous edition. New classes include LexiconInformation and GrammaticalInformation.
The Representation class has been renamed the OrthographicRepresentation class. In addition, the
OrthographicRepresentation subclasses, FormRepresentation and TextRepresentation, no longer are
part of the core model, providing it with greater modeling flexibility. The LexicalEntry subclass now
allows subclasses, providing improved extensibility and flexibility for modeling future parts. The
addition of the CrossREF class and associated metadata provides a formal model for cross-reference
design and implementation, closing a functional gap in the previous edition. A thoroughly revised
description of data category allocation mechanisms and their relationship to generalization by typing
provides a more incisive description of how these interdependent mechanisms enable flexible and
extensible designs.
A list of all parts in the ISO 24613 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved

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.
[3]
LMF supports existing lexical resource models such as Genelex , the EAGLES International Standard
[4] [10]
for Language Engineering (ISLE) , Multilingual ISLE Lexical Entry (MILE) models , Text Encoding
[8] [7]
Initiative (TEI) guidelines , Ontolex , and the Language Base Exchange (LBX) serialization together
[5]
with the U.S. Government Wordscape On-Line Dictionary system .
[9]
LMF uses UML modeling processes . The LMF core package describes the basic hierarchy of information
of a lexical entry, including information on the word 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 in additional LMF parts (see Annex A for data category examples);
— 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.
LMF parts 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.
The parts currently in or planned for the new organization of ISO 24613 include Part 1: Core model, Part
2: Machine readable dictionary (MRD) model, Part 3: Diachrony-etymology, Part 4: TEI serialization, Part
5: LBX serialization, and Part 6: Syntax and semantics.
[2]
The ISO 24613 series is designed to coordinate closely with ISO 16642 .
INTERNATIONAL STANDARD ISO 24613-1:2019(E)
Language resource management — Lexical markup
framework (LMF) —
Part 1:
Core model
1 Scope
This document describes the core model of the lexical markup framework (LMF)l, a metamodel for
representing data in monolingual and multilingual lexical databases used with computer applications.
LMF provides mechanisms that allow the development and integration of a variety of electronic lexical
resource types.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 15924, Information and documentation — Codes for the representation of names of scripts
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
data category
DC
elementary descriptor used in a linguistic description or annotation scheme
3.2
word form
instance of a word, multi-word expression, root, stem, or morpheme
3.3
grammatical feature
property associated with a word form (3.2) to describe one of its grammatical attributes
EXAMPLE /grammatical gender/
3.4
lemma
lemmatized form
canonical form
conventional word form (3.2) chosen to represent a lexeme (3.5)
Note 1 to entry: In many European languages, the lemma is usually the /singular/ for a noun 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 sometimes considered as being the third person singular with the accomplished aspect, in
other approaches it is considered as being the root.
3.5
lexeme
abstract unit generally associated with a set of word forms (3.2) sharing a common meaning
[SOURCE: ISO 24613:2008, 3.25, modified – "forms" replaced with "word forms".]
3.6
lexical resource
lexical database
database consisting of one or several lexicons (3.7)
3.7
lexicon
resource comprising lexical entries for one or several languages
Note 1 to entry: A special language lexicon or a lexicon prepared for a specific NLP application can comprise a
specific subset of a language.
3.8
multiword expression
MWE
lexeme (3.5) made up of a sequence of two or more lexemes that has properties that may not be
predictable from the properties of the individual lexemes or their normal mode of combination
EXAMPLE “To kick the bucket”, an idiomatic expression which means to die rather than to hit a bucket with
one's foot. An idiomatic expression is a subtype of MWE whose properties are not predictable from the properties
of the individual lexemes.
Note 1 to entry: 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 (3.13).
3.9
natural language processing
NLP
field covering knowledge and techniques involved in the processing of linguistic data by a computer
3.10
orthography
way of spelling or writing lexemes (3.5) that conforms to a conventionalized use
Note 1 to entry: Usually, the notion of orthography covers standardized spellings of alphabetic languages, such
as standard UK or US English, or reformed German spelling, as well as hieroglyphic or syllabic writing systems.
For the purpose of this standard, we also subsume variations such as transliterations of languages in non-native
scripts, stenographic renderings, or representations in the International Phonetic Alphabet under the notion of
orthography.
2 © ISO 2019 – All rights reserved

3.11
part of speech
lexical category
word class
category assigned to a lexeme (3.5) based on its grammatical properties
EXAMPLE Typical parts of speech for European languages include: noun, verb, a
...

INTERNATIONAL ISO
STANDARD 24613-1
First edition
2019-06
Language resource management —
Lexical markup framework (LMF) —
Part 1:
Core model
Gestion des ressources linguistiques — Cadre de balisage lexical
(LMF) —
Partie 1: Modèle de base
Reference number
©
ISO 2019
© ISO 2019
All rights reserved. Unless otherwise specified, or required in the context of its implementation, no part of this publication may
be reproduced or utilized otherwise in any form or by any means, electronic or mechanical, including photocopying, or posting
on the internet or an intranet, without prior written permission. Permission can be requested from either ISO at the address
below or ISO’s member body in the country of the requester.
ISO copyright office
CP 401 • Ch. de Blandonnet 8
CH-1214 Vernier, Geneva
Phone: [phone]
Fax: [phone]
Email: [e-mail]
Website: www.iso.org
Published in Switzerland
ii © ISO 2019 – All rights reserved

Contents Page
Foreword .iv
Introduction .v
1 Scope . 1
2 Normative references . 1
3 Terms and definitions . 1
4 Key standards used by LMF . 3
4.1 Unicode . 3
4.2 Language coding . 3
4.3 Script coding . 3
4.4 Unified modeling language (UML) . 3
5 The LMF model . 3
5.1 Introduction . 3
5.2 Class inheritance and data category selection procedures . 4
5.2.1 Class inheritance . 4
5.2.2 LMF attributes . . 4
5.2.3 Data category selection (DCS) . 4
5.2.4 User-defined data categories . 4
5.3 LMF core package . 4
5.3.1 General. 4
5.3.2 LexicalResource class . 5
5.3.3 GlobalInformation class . 5
5.3.4 Lexicon class . 6
5.3.5 LexiconInformation class . 6
5.3.6 LexicalEntry class . 6
5.3.7 Form class . 6
5.3.8 OrthographicRepresentation class . 6
5.3.9 GrammaticalInformation Class . 6
5.3.10 Sense class . 7
5.3.11 Definition class . 7
5.4 Cross reference (CrossREF) model . 7
5.4.1 General. 7
5.4.2 CrossREF and CrossREFConstraint classes . 7
5.4.3 CrossREFConstraint class . 7
5.5 Methods for data category selection and subclass creation . 7
5.5.1 General. 7
5.5.2 Generalization (typing) . 8
5.5.3 Object instantiation . 8
5.5.4 Design choices . 8
5.5.5 Data categories for orthographic representation . 9
5.5.6 Principles for model simplification. 9
5.6 LMF extension use . 9
5.6.1 General. 9
5.6.2 Lexicon comparison .10
Annex A (informative) Data category examples .11
Bibliography .13
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.
The procedures used to develop this document and those intended for its further maintenance are
described in the ISO/IEC Directives, Part 1. In particular, the different approval criteria needed for the
different types of ISO documents should be noted. This document was drafted in accordance with the
editorial rules of the ISO/IEC Directives, Part 2 (see www .iso .org/directives).
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. Details of
any patent rights identified during the development of the document will be in the Introduction and/or
on the ISO list of patent declarations received (see www .iso .org/patents).
Any trade name used in this document is information given for the convenience of users and does not
constitute an endorsement.
For an explanation of the voluntary nature of standards, the meaning of ISO specific terms and
expressions related to conformity assessment, as well as information about ISO's adherence to the
World Trade Organization (WTO) principles in the Technical Barriers to Trade (TBT), see www .iso
.org/iso/foreword .html.
The document was prepared by Technical Committee ISO/TC 37, Language and terminology,
Subcommittee 4, Language resource management.
This first edition of ISO 24613-1, together with ISO 24613-2 to ISO 24613-6, cancels and replaces
ISO 24613:2008, which has been technically revised.
The main changes compared to the previous edition are as follows:
The content has been entirely revised and subdivided into parts. Part 1, Core model, contains the
body of the previous edition. New classes include LexiconInformation and GrammaticalInformation.
The Representation class has been renamed the OrthographicRepresentation class. In addition, the
OrthographicRepresentation subclasses, FormRepresentation and TextRepresentation, no longer are
part of the core model, providing it with greater modeling flexibility. The LexicalEntry subclass now
allows subclasses, providing improved extensibility and flexibility for modeling future parts. The
addition of the CrossREF class and associated metadata provides a formal model for cross-reference
design and implementation, closing a functional gap in the previous edition. A thoroughly revised
description of data category allocation mechanisms and their relationship to generalization by typing
provides a more incisive description of how these interdependent mechanisms enable flexible and
extensible designs.
A list of all parts in the ISO 24613 series can be found on the ISO website.
Any feedback or questions on this document should be directed to the user’s national standards body. A
complete listing of these bodies can be found at www .iso .org/members .html.
iv © ISO 2019 – All rights reserved

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.
[3]
LMF supports existing lexical resource models such as Genelex , the EAGLES International Standard
[4] [10]
for Language Engineering (ISLE) , Multilingual ISLE Lexical Entry (MILE) models , Text Encoding
[8] [7]
Initiative (TEI) guidelines , Ontolex , and the Language Base Exchange (LBX) serialization together
[5]
with the U.S. Government Wordscape On-Line Dictionary system .
[9]
LMF uses UML modeling processes . The LMF core package describes the basic hierarchy of information
of a lexical entry, including information on the word 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 in additional LMF parts (see Annex A for data category examples);
— 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.
LMF parts 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.
The parts currently in or planned for the new organization of ISO 24613 include Part 1: Core model, Part
2: Machine readable dictionary (MRD) model, Part 3: Diachrony-etymology, Part 4: TEI serialization, Part
5: LBX serialization, and Part 6: Syntax and semantics.
[2]
The ISO 24613 series is designed to coordinate closely with ISO 16642 .
INTERNATIONAL STANDARD ISO 24613-1:2019(E)
Language resource management — Lexical markup
framework (LMF) —
Part 1:
Core model
1 Scope
This document describes the core model of the lexical markup framework (LMF)l, a metamodel for
representing data in monolingual and multilingual lexical databases used with computer applications.
LMF provides mechanisms that allow the development and integration of a variety of electronic lexical
resource types.
2 Normative references
The following documents are referred to in the text in such a way that some or all of their content
constitutes requirements 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 15924, Information and documentation — Codes for the representation of names of scripts
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
ISO and IEC maintain terminological databases for use in standardization at the following addresses:
— ISO Online browsing platform: available at http: //www .iso .org/obp
— IEC Electropedia: available at http: //www .electropedia .org/
3.1
data category
DC
elementary descriptor used in a linguistic description or annotation scheme
3.2
word form
instance of a word, multi-word expression, root, stem, or morpheme
3.3
grammatical feature
property associated with a word form (3.2) to describe one of its grammatical attributes
EXAMPLE /grammatical gender/
3.4
lemma
lemmatized form
canonical form
conventional word form (3.2) chosen to represent a lexeme (3.5)
Note 1 to entry: In many European languages, the lemma is usually the /singular/ for a noun 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 sometimes considered as being the third person singular with the accomplished aspect, in
other approaches it is considered as being the root.
3.5
lexeme
abstract unit generally associated with a set of word forms (3.2) sharing a common meaning
[SOURCE: ISO 24613:2008, 3.25, modified – "forms" replaced with "word forms".]
3.6
lexical resource
lexical database
database consisting of one or several lexicons (3.7)
3.7
lexicon
resource comprising lexical entries for one or several languages
Note 1 to entry: A special language lexicon or a lexicon prepared for a specific NLP application can comprise a
specific subset of a language.
3.8
multiword expression
MWE
lexeme (3.5) made up of a sequence of two or more lexemes that has properties that may not be
predictable from the properties of the individual lexemes or their normal mode of combination
EXAMPLE “To kick the bucket”, an idiomatic expression which means to die rather than to hit a bucket with
one's foot. An idiomatic expression is a subtype of MWE whose properties are not predictable from the properties
of the individual lexemes.
Note 1 to entry: 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 (3.13).
3.9
natural language processing
NLP
field covering knowledge and techniques involved in the processing of linguistic data by a computer
3.10
orthography
way of spelling or writing lexemes (3.5) that conforms to a conventionalized use
Note 1 to entry: Usually, the notion of orthography covers standardized spellings of alphabetic languages, such
as standard UK or US English, or reformed German spelling, as well as hieroglyphic or syllabic writing systems.
For the purpose of this standard, we also subsume variations such as transliterations of languages in non-native
scripts, stenographic renderings, or representations in the International Phonetic Alphabet under the notion of
orthography.
2 © ISO 2019 – All rights reserved

3.11
part of speech
lexical category
word class
category assigned to a lexeme (3.5) based on its grammatical properties
EXAMPLE Typical parts of speech for European languages include: noun, verb, adjective, adverb,
preposition, etc.
3.12
script
set of graphic characters used for the written form of one or more languages
EXAMPLE Hiragana, Katakana, Latin and Cyrillic.
Note 1 to entry: 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.
[SOURCE: ISO/IEC 10646:2017 3.50, modified – Example and Note 1 to entry added]
4 Key
...