draft-ietf-ltru-registry-10.txt   draft-ietf-ltru-registry-11.txt 
Network Working Group A. Phillips, Ed. Network Working Group A. Phillips, Ed.
Internet-Draft Quest Software Internet-Draft Quest Software
Expires: February 5, 2006 M. Davis, Ed. Expires: February 16, 2006 M. Davis, Ed.
IBM IBM
August 04, 2005 August 15, 2005
Tags for Identifying Languages Tags for Identifying Languages
draft-ietf-ltru-registry-10 draft-ietf-ltru-registry-11
Status of this Memo Status of this Memo
By submitting this Internet-Draft, each author represents that any By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79. aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that Task Force (IETF), its areas, and its working groups. Note that
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and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
The list of current Internet-Drafts can be accessed at The list of current Internet-Drafts can be accessed at
http://www.ietf.org/ietf/1id-abstracts.txt. http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html. http://www.ietf.org/shadow.html.
This Internet-Draft will expire on February 5, 2006. This Internet-Draft will expire on February 16, 2006.
Copyright Notice Copyright Notice
Copyright (C) The Internet Society (2005). Copyright (C) The Internet Society (2005).
Abstract Abstract
This document describes the structure, content, construction, and This document describes the structure, content, construction, and
semantics of language tags for use in cases where it is desirable to semantics of language tags for use in cases where it is desirable to
indicate the language used in an information object. It also indicate the language used in an information object. It also
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2.2.3 Script Subtag . . . . . . . . . . . . . . . . . . . . 10 2.2.3 Script Subtag . . . . . . . . . . . . . . . . . . . . 10
2.2.4 Region Subtag . . . . . . . . . . . . . . . . . . . . 11 2.2.4 Region Subtag . . . . . . . . . . . . . . . . . . . . 11
2.2.5 Variant Subtags . . . . . . . . . . . . . . . . . . . 13 2.2.5 Variant Subtags . . . . . . . . . . . . . . . . . . . 13
2.2.6 Extension Subtags . . . . . . . . . . . . . . . . . . 14 2.2.6 Extension Subtags . . . . . . . . . . . . . . . . . . 14
2.2.7 Private Use Subtags . . . . . . . . . . . . . . . . . 15 2.2.7 Private Use Subtags . . . . . . . . . . . . . . . . . 15
2.2.8 Pre-Existing RFC 3066 Registrations . . . . . . . . . 16 2.2.8 Pre-Existing RFC 3066 Registrations . . . . . . . . . 16
2.2.9 Classes of Conformance . . . . . . . . . . . . . . . . 16 2.2.9 Classes of Conformance . . . . . . . . . . . . . . . . 16
3. Registry Format and Maintenance . . . . . . . . . . . . . . . 18 3. Registry Format and Maintenance . . . . . . . . . . . . . . . 18
3.1 Format of the IANA Language Subtag Registry . . . . . . . 18 3.1 Format of the IANA Language Subtag Registry . . . . . . . 18
3.2 Maintenance of the Registry . . . . . . . . . . . . . . . 23 3.2 Maintenance of the Registry . . . . . . . . . . . . . . . 23
3.3 Stability of IANA Registry Entries . . . . . . . . . . . . 25 3.3 Stability of IANA Registry Entries . . . . . . . . . . . . 24
3.4 Registration Procedure for Subtags . . . . . . . . . . . . 28 3.4 Registration Procedure for Subtags . . . . . . . . . . . . 28
3.5 Possibilities for Registration . . . . . . . . . . . . . . 31 3.5 Possibilities for Registration . . . . . . . . . . . . . . 31
3.6 Extensions and Extensions Namespace . . . . . . . . . . . 33 3.6 Extensions and Extensions Registry . . . . . . . . . . . . 33
3.7 Initialization of the Registry . . . . . . . . . . . . . . 36 3.7 Initialization of the Registries . . . . . . . . . . . . . 36
4. Formation and Processing of Language Tags . . . . . . . . . . 37 4. Formation and Processing of Language Tags . . . . . . . . . . 37
4.1 Choice of Language Tag . . . . . . . . . . . . . . . . . . 37 4.1 Choice of Language Tag . . . . . . . . . . . . . . . . . . 37
4.2 Meaning of the Language Tag . . . . . . . . . . . . . . . 39 4.2 Meaning of the Language Tag . . . . . . . . . . . . . . . 39
4.3 Length Considerations . . . . . . . . . . . . . . . . . . 40 4.3 Length Considerations . . . . . . . . . . . . . . . . . . 40
4.3.1 Working with Limited Buffer Sizes . . . . . . . . . . 40 4.3.1 Working with Limited Buffer Sizes . . . . . . . . . . 40
4.3.2 Truncation of Language Tags . . . . . . . . . . . . . 42 4.3.2 Truncation of Language Tags . . . . . . . . . . . . . 42
4.4 Canonicalization of Language Tags . . . . . . . . . . . . 42 4.4 Canonicalization of Language Tags . . . . . . . . . . . . 42
4.5 Considerations for Private Use Subtags . . . . . . . . . . 44 4.5 Considerations for Private Use Subtags . . . . . . . . . . 44
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46 5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 46
5.1 Language Subtag Registry . . . . . . . . . . . . . . . . . 46 5.1 Language Subtag Registry . . . . . . . . . . . . . . . . . 46
5.2 Extensions Registry . . . . . . . . . . . . . . . . . . . 47 5.2 Extensions Registry . . . . . . . . . . . . . . . . . . . 47
6. Security Considerations . . . . . . . . . . . . . . . . . . . 48 6. Security Considerations . . . . . . . . . . . . . . . . . . . 48
7. Character Set Considerations . . . . . . . . . . . . . . . . . 49 7. Character Set Considerations . . . . . . . . . . . . . . . . . 49
8. Changes from RFC 3066 . . . . . . . . . . . . . . . . . . . . 50 8. Changes from RFC 3066 . . . . . . . . . . . . . . . . . . . . 50
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 55 9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 53
9.1 Normative References . . . . . . . . . . . . . . . . . . . 55 9.1 Normative References . . . . . . . . . . . . . . . . . . . 53
9.2 Informative References . . . . . . . . . . . . . . . . . . 56 9.2 Informative References . . . . . . . . . . . . . . . . . . 54
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 57 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . 55
A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 58 A. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 56
B. Examples of Language Tags (Informative) . . . . . . . . . . . 59 B. Examples of Language Tags (Informative) . . . . . . . . . . . 57
Intellectual Property and Copyright Statements . . . . . . . . 62 Intellectual Property and Copyright Statements . . . . . . . . 60
1. Introduction 1. Introduction
Human beings on our planet have, past and present, used a number of Human beings on our planet have, past and present, used a number of
languages. There are many reasons why one would want to identify the languages. There are many reasons why one would want to identify the
language used when presenting or requesting information. language used when presenting or requesting information.
User's language preferences often need to be identified so that User's language preferences often need to be identified so that
appropriate processing can be applied. For example, the user's appropriate processing can be applied. For example, the user's
language preferences in a Web browser can be used to select Web pages language preferences in a Web browser can be used to select Web pages
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mapped directly to their US-ASCII lowercase equivalents in the range mapped directly to their US-ASCII lowercase equivalents in the range
'a' through 'z'. Thus the tag "mn-Cyrl-MN" is not distinct from "MN- 'a' through 'z'. Thus the tag "mn-Cyrl-MN" is not distinct from "MN-
cYRL-mn" or "mN-cYrL-Mn" (or any other combination) and each of these cYRL-mn" or "mN-cYrL-Mn" (or any other combination) and each of these
variations conveys the same meaning: Mongolian written in the variations conveys the same meaning: Mongolian written in the
Cyrillic script as used in Mongolia. Cyrillic script as used in Mongolia.
2.2 Language Subtag Sources and Interpretation 2.2 Language Subtag Sources and Interpretation
The namespace of language tags and their subtags is administered by The namespace of language tags and their subtags is administered by
the Internet Assigned Numbers Authority (IANA) [RFC2860] according to the Internet Assigned Numbers Authority (IANA) [RFC2860] according to
the rules in Section 5 of this document. The registry maintained by the rules in Section 5 of this document. The Language Subtag
IANA is the source for valid subtags: other standards referenced in Registry maintained by IANA is the source for valid subtags: other
this section provide the source material for that registry. standards referenced in this section provide the source material for
that registry.
Terminology in this section: Terminology in this section:
o Tag or tags refers to a complete language tag, such as o Tag or tags refers to a complete language tag, such as
"fr-Latn-CA". Examples of tags in this document are enclosed in "fr-Latn-CA". Examples of tags in this document are enclosed in
double-quotes ("en-US"). double-quotes ("en-US").
o Subtag refers to a specific section of a tag, delimited by hyphen, o Subtag refers to a specific section of a tag, delimited by hyphen,
such as the subtag 'Latn' in "fr-Latn-CA". Examples of subtags in such as the subtag 'Latn' in "fr-Latn-CA". Examples of subtags in
this document are enclosed in single quotes ('Latn'). this document are enclosed in single quotes ('Latn').
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with '1996', then 'example' should include two Prefix fields: "de" with '1996', then 'example' should include two Prefix fields: "de"
and "de-1996". and "de-1996".
2.2.6 Extension Subtags 2.2.6 Extension Subtags
Extensions provide a mechanism for extending language tags for use in Extensions provide a mechanism for extending language tags for use in
various applications. See: Section 3.6. The following rules apply various applications. See: Section 3.6. The following rules apply
to extensions: to extensions:
1. Extension subtags are separated from the other subtags defined 1. Extension subtags are separated from the other subtags defined
in this document by a single-letter subtag ("singleton"). The in this document by a single character subtag ("singleton").
singleton MUST be one allocated to a registration authority via The singleton MUST be one allocated to a registration authority
the mechanism described in Section 3.6 and MUST NOT be the via the mechanism described in Section 3.6 and MUST NOT be the
letter 'x', which is reserved for private use subtag sequences. letter 'x', which is reserved for private use subtag sequences.
2. Note: Private use subtag sequences starting with the singleton 2. Note: Private use subtag sequences starting with the singleton
subtag 'x' are described below. subtag 'x' are described below.
3. An extension MUST follow at least a primary language subtag. 3. An extension MUST follow at least a primary language subtag.
That is, a language tag cannot begin with an extension. That is, a language tag cannot begin with an extension.
Extensions extend language tags, they do not override or replace Extensions extend language tags, they do not override or replace
them. For example, "a-value" is not a well-formed language tag, them. For example, "a-value" is not a well-formed language tag,
while "de-a-value" is. while "de-a-value" is.
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o For variant and extended language subtags, if the registry o For variant and extended language subtags, if the registry
contains one or more 'Prefix' fields for that subtag, check that contains one or more 'Prefix' fields for that subtag, check that
the tag matches at least one prefix. The tag matches if all the the tag matches at least one prefix. The tag matches if all the
subtags in the 'Prefix' also appear in the tag. For example, the subtags in the 'Prefix' also appear in the tag. For example, the
prefix "es-CO" matches the tag "es-Latn-CO-x-private" because both prefix "es-CO" matches the tag "es-Latn-CO-x-private" because both
the 'es' language subtag and 'CO' region subtag appear in the tag. the 'es' language subtag and 'CO' region subtag appear in the tag.
3. Registry Format and Maintenance 3. Registry Format and Maintenance
This section defines the Language Subtag Registry and the maintenance This section defines the Language Subtag Registry and the maintenance
and update procedures associated with it. and update procedures associated with it, as well as a registry for
extensions to language tags (Section 3.6).
The language subtag registry will be maintained so that, except for The Language Subtag Registry contains a comprehensive list of all of
the subtags valid in language tags. This allows implementers a
straightforward and reliable way to validate language tags. The
Language Subtag Registry will be maintained so that, except for
extension subtags, it is possible to validate all of the subtags that extension subtags, it is possible to validate all of the subtags that
appear in a language tag under the provisions of this document or its appear in a language tag under the provisions of this document or its
revisions or successors. In addition, the meaning of the various revisions or successors. In addition, the meaning of the various
subtags will be unambiguous and stable over time. (The meaning of subtags will be unambiguous and stable over time. (The meaning of
private use subtags, of course, is not defined by the IANA registry.) private use subtags, of course, is not defined by the IANA registry.)
The registry defined under this document contains a comprehensive
list of all of the subtags valid in language tags. This allows
implementers a straightforward and reliable way to validate language
tags.
3.1 Format of the IANA Language Subtag Registry 3.1 Format of the IANA Language Subtag Registry
The IANA Language Subtag Registry ("the registry") consists of a text The IANA Language Subtag Registry ("the registry") consists of a text
file that is machine readable in the format described in this file that is machine readable in the format described in this
section, plus copies of the registration forms approved by the section, plus copies of the registration forms approved by the
Language Subtag Reviewer in accordance with the process described in Language Subtag Reviewer in accordance with the process described in
Section 3.4. With the exception of the registration forms for Section 3.4. With the exception of the registration forms for
grandfathered and redundant tags, no registration records will be grandfathered and redundant tags, no registration records will be
maintained for the initial set of subtags. maintained for the initial set of subtags.
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Statistical Services Branch Statistical Services Branch
Statistics Division Statistics Division
United Nations, Room DC2-1620 United Nations, Room DC2-1620
New York, NY 10017, USA New York, NY 10017, USA
Fax: +1-212-963-0623 Fax: +1-212-963-0623
E-mail: statistics@un.org E-mail: statistics@un.org
URL: http://unstats.un.org/unsd/methods/m49/m49alpha.htm URL: http://unstats.un.org/unsd/methods/m49/m49alpha.htm
3.6 Extensions and Extensions Namespace 3.6 Extensions and Extensions Registry
Extension subtags are those introduced by single-letter subtags other Extension subtags are those introduced by single character subtags
than 'x'. They are reserved for the generation of identifiers which ("singletons") other than 'x'. They are reserved for the generation
contain a language component, and are compatible with applications of identifiers which contain a language component, and are compatible
that understand language tags. with applications that understand language tags.
The structure and form of extensions are defined by this document so The structure and form of extensions are defined by this document so
that implementations can be created that are forward compatible with that implementations can be created that are forward compatible with
applications that might be created using single-letter subtags in the applications that might be created using singletons in the future.
future. In addition, defining a mechanism for maintaining single- In addition, defining a mechanism for maintaining singletons will
letter subtags will lend stability to this document by reducing the lend stability to this document by reducing the likely need for
likely need for future revisions or updates. future revisions or updates.
Single-letter subtags are to be assigned by IANA using the "IETF Single character subtags are assigned by IANA using the "IETF
Consensus" policy defined by [RFC2434]. This policy requires the Consensus" policy defined by [RFC2434]. This policy requires the
development of an RFC, which SHALL define the name, purpose, development of an RFC, which SHALL define the name, purpose,
processes, and procedures for maintaining the subtags. The processes, and procedures for maintaining the subtags. The
maintaining or registering authority, including name, contact email, maintaining or registering authority, including name, contact email,
discussion list email, and URL location of the registry MUST be discussion list email, and URL location of the registry MUST be
indicated clearly in the RFC. The RFC MUST specify or include each indicated clearly in the RFC. The RFC MUST specify or include each
of the following: of the following:
o The specification MUST reference the specific version or revision o The specification MUST reference the specific version or revision
of this document that governs its creation and MUST reference this of this document that governs its creation and MUST reference this
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once defined by a specification, MUST NOT be retracted or change once defined by a specification, MUST NOT be retracted or change
in meaning in any substantial way. in meaning in any substantial way.
o The specification MUST include in a separate section the o The specification MUST include in a separate section the
registration form reproduced in this section (below) to be used in registration form reproduced in this section (below) to be used in
registering the extension upon publication as an RFC. registering the extension upon publication as an RFC.
o IANA MUST be informed of changes to the contact information and o IANA MUST be informed of changes to the contact information and
URL for the specification. URL for the specification.
IANA will maintain a registry of allocated single-letter (singleton) IANA will maintain a registry of allocated single character
subtags. This registry MUST use the record-jar format described by (singleton) subtags. This registry MUST use the record-jar format
the ABNF in Section 3.1. Upon publication of an extension as an RFC, described by the ABNF in Section 3.1. Upon publication of an
the maintaining authority defined in the RFC MUST forward this extension as an RFC, the maintaining authority defined in the RFC
registration form to iesg@ietf.org, who MUST forward the request to MUST forward this registration form to iesg@ietf.org, who MUST
iana@iana.org. The maintaining authority of the extension MUST forward the request to iana@iana.org. The maintaining authority of
maintain the accuracy of the record by sending an updated full copy the extension MUST maintain the accuracy of the record by sending an
of the record to iana@iana.org with the subject line "LANGUAGE TAG updated full copy of the record to iana@iana.org with the subject
EXTENSION UPDATE" whenever content changes. Only the 'Comments', line "LANGUAGE TAG EXTENSION UPDATE" whenever content changes. Only
'Contact_Email', 'Mailing_List', and 'URL' fields MAY be modified in the 'Comments', 'Contact_Email', 'Mailing_List', and 'URL' fields MAY
these updates. be modified in these updates.
Failure to maintain this record, the corresponding registry, or meet Failure to maintain this record, the corresponding registry, or meet
other conditions imposed by this section of this document MAY be other conditions imposed by this section of this document MAY be
appealed to the IESG [RFC2028] under the same rules as other IETF appealed to the IESG [RFC2028] under the same rules as other IETF
decisions (see [RFC2026]) and MAY result in the authority to maintain decisions (see [RFC2026]) and MAY result in the authority to maintain
the extension being withdrawn or reassigned by the IESG. the extension being withdrawn or reassigned by the IESG.
%% %%
Identifier: Identifier:
Description: Description:
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Added: Added:
RFC: RFC:
Authority: Authority:
Contact_Email: Contact_Email:
Mailing_List: Mailing_List:
URL: URL:
%% %%
Figure 6: Format of Records in the Language Tag Extensions Registry Figure 6: Format of Records in the Language Tag Extensions Registry
'Identifier' contains the single letter subtag (singleton) assigned 'Identifier' contains the single character subtag (singleton)
to the extension. The Internet-Draft submitted to define the assigned to the extension. The Internet-Draft submitted to define
extension SHOULD specify which letter to use, although the IESG MAY the extension SHOULD specify which letter or digit to use, although
change the assignment when approving the RFC. the IESG MAY change the assignment when approving the RFC.
'Description' contains the name and description of the extension. 'Description' contains the name and description of the extension.
'Comments' is an OPTIONAL field and MAY contain a broader description 'Comments' is an OPTIONAL field and MAY contain a broader description
of the extension. of the extension.
'Added' contains the date the RFC was published in the "full-date" 'Added' contains the date the RFC was published in the "full-date"
format specified in [RFC3339]. For example: 2004-06-28 represents format specified in [RFC3339]. For example: 2004-06-28 represents
June 28, 2004, in the Gregorian calendar. June 28, 2004, in the Gregorian calendar.
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that the most significant information be in the most significant that the most significant information be in the most significant
(left-most) subtags, and that the specification gracefully handle (left-most) subtags, and that the specification gracefully handle
truncated subtags. truncated subtags.
When a language tag is to be used in a specific, known, protocol, it When a language tag is to be used in a specific, known, protocol, it
is RECOMMENDED that that the language tag not contain extensions not is RECOMMENDED that that the language tag not contain extensions not
supported by that protocol. In addition, note that some protocols supported by that protocol. In addition, note that some protocols
MAY impose upper limits on the length of the strings used to store or MAY impose upper limits on the length of the strings used to store or
transport the language tag. transport the language tag.
3.7 Initialization of the Registry 3.7 Initialization of the Registries
Adoption of this document will REQUIRE an initial version of the Upon adoption of this document an initial version of the Language
registry containing the various subtags initially valid in a language Subtag Registry containing the various subtags initially valid in a
tag. This collection of subtags, along with a description of the language tag is necessary. This collection of subtags, along with a
process used to create it, is described by [initial-registry]. description of the process used to create it, is described by
[initial-registry].
Registrations that are in process under the rules defined in Registrations that are in process under the rules defined in
[RFC3066] when this document is adopted MAY be completed under the [RFC3066] when this document is adopted MAY be completed under the
former rules, at the discretion of the language tag reviewer. Any former rules, at the discretion of the language tag reviewer. Any
new registrations submitted after the adoption of this document MUST new registrations submitted after the adoption of this document MUST
be rejected. be rejected.
An initial version of the Language Extension Registry described in
Section 3.6 is also needed. The Language Extension Registry SHALL be
initialized with a single record containing a single field of type
"File-Date" as a placeholder for future assignments.
4. Formation and Processing of Language Tags 4. Formation and Processing of Language Tags
This section addresses how to use the information in the registry This section addresses how to use the information in the registry
with the tag syntax to choose, form and process language tags. with the tag syntax to choose, form and process language tags.
4.1 Choice of Language Tag 4.1 Choice of Language Tag
One is sometimes faced with the choice between several possible tags One is sometimes faced with the choice between several possible tags
for the same body of text. for the same body of text.
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region subtags respectively. region subtags respectively.
o Adds a well-defined extension mechanism. o Adds a well-defined extension mechanism.
o Defines an extended language subtag, possibly for use with certain o Defines an extended language subtag, possibly for use with certain
anticipated features of ISO 639-3. anticipated features of ISO 639-3.
Ed Note: The following items are provided for the convenience of Ed Note: The following items are provided for the convenience of
reviewers and will be removed from the final document. reviewers and will be removed from the final document.
Changes between draft-ietf-ltru-registry-09 and this version are: Changes between draft-ietf-ltru-registry-10 and this version are:
o Incorporated John Cowan's list of nits selectively by looking at
the context. RFC 2119 word changes listed. (#1026
thread)(J.Cowan)
* could be used => MAY in Section 4.5
* cannot => MUST NOT in Section 3.6
* can raise objections => MAY in Section 3.4
* can be registered => MAY in Section 3.5
* will not be added => MUST in Section 2.2.1
* will evaluate => MUST in Section 3.2
* 'no new entries will be added and none of the entries removed'
made normative in Section 3.2
* 'No subtags will be registered' => 'Subtags MUST NOT be
registered' in Section 3.5
* will use, will forward => MUST in Section 3.6
* will be relabeled, will be sent => MUST in Section 5.1
* will be limited => SHALL in Section 5.1
* will include => MUST in Section 5.2
o Changed the introductory paragraph to avoid the loaded word
"defined" (M.Duerst, JFC Morfin)
o Added clarification to the "Compatibility" paragraph just above
(M.Davis)
o Modified the introduction to Section 2. (M.Gunn)
o Added formal reference links to [RFC3066] and [RFC1766] in
Section 1 (S.Hollenbeck)
o Added a reference to [RFC2234bis] to the reference to ABNF %2D in
Section 2.1 (S.Hollenbeck)
o Added a normative reference to [ISO646] and referenced it in
Section 2.1 (S.Hollenbeck)
o Changed "MUST not" to "MUST NOT" in Section 2.1 (S.Hollenbeck)
o Changed "MAY NOT" (which isn't RFC 2119 defined) to read
"...records of type 'region' sometimes does not represent..." in
Section 3.1 (S.Hollenbeck)
o Referenced RFC2434 and "IETF Consensus" policy in Section 3.6
(S.Hollenbeck)
o Adjusted an introduction paragraph in order to have a forward o Changed the text describing extensions from "single-letter" to
reference to the subtag registry. (P.Constable) "single character" or "singleton" to be consistent with the ABNF
o Beautified the ABNF (K.Karlsson) and the WG's intentions (D.Ewell)
o Beautified the registration form artwork by adding some indention o Made RFC 2047, RFC 2781, and RFC 3552 into informative references
(F.Ellermann) (#1095)(K.Karlsson)
o Other minor editorial nits. (F.Ellermann) o Made modifications to clarify the difference between the Language
Subtag Registry and the Language Extensions Registry (K.Karlsson)
o Removed the "locale identifiers" sentence. (#1067) (R.Presuhn) o Inserted some text to ensure that the Language Extensions Registry
is initialized properly (#1103) (K.Karlsson)
9. References 9. References
9.1 Normative References 9.1 Normative References
[ISO10646] [ISO10646]
International Organization for Standardization, "ISO/IEC International Organization for Standardization, "ISO/IEC
10646:2003. Information technology -- Universal Multiple- 10646:2003. Information technology -- Universal Multiple-
Octet Coded Character Set (UCS), as, from time to time, Octet Coded Character Set (UCS)", 2003.
amended, replaced by a new edition or expanded by the
addition of new parts", 2003.
[ISO15924] [ISO15924]
International Organization for Standardization, "ISO International Organization for Standardization, "ISO
15924:2004. Information and documentation -- Codes for the 15924:2004. Information and documentation -- Codes for the
representation of names of scripts", January 2004. representation of names of scripts", January 2004.
[ISO3166-1] [ISO3166-1]
International Organization for Standardization, "ISO 3166- International Organization for Standardization, "ISO 3166-
1:1997. Codes for the representation of names of 1:1997. Codes for the representation of names of
countries and their subdivisions -- Part 1: Country countries and their subdivisions -- Part 1: Country
skipping to change at page 55, line 37 skipping to change at page 53, line 35
[ISO639-1] [ISO639-1]
International Organization for Standardization, "ISO 639- International Organization for Standardization, "ISO 639-
1:2002. Codes for the representation of names of languages 1:2002. Codes for the representation of names of languages
-- Part 1: Alpha-2 code", 2002. -- Part 1: Alpha-2 code", 2002.
[ISO639-2] [ISO639-2]
International Organization for Standardization, "ISO 639- International Organization for Standardization, "ISO 639-
2:1998. Codes for the representation of names of languages 2:1998. Codes for the representation of names of languages
-- Part 2: Alpha-3 code, first edition", 1998. -- Part 2: Alpha-3 code, first edition", 1998.
[ISO646] ISO/IEC 646 JTC 1/SC 2, "ISO/IEC 646:1991, Information [ISO646] International Organization for Standardization, "ISO/IEC
technology -- ISO 7-bit coded character set for 646:1991, Information technology -- ISO 7-bit coded
information interchange.", 1991. character set for information interchange.", 1991.
[RFC2026] Bradner, S., "The Internet Standards Process -- Revision [RFC2026] Bradner, S., "The Internet Standards Process -- Revision
3", BCP 9, RFC 2026, October 1996. 3", BCP 9, RFC 2026, October 1996.
[RFC2028] Hovey, R. and S. Bradner, "The Organizations Involved in [RFC2028] Hovey, R. and S. Bradner, "The Organizations Involved in
the IETF Standards Process", BCP 11, RFC 2028, the IETF Standards Process", BCP 11, RFC 2028,
October 1996. October 1996.
[RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Three: Message Header Extensions for Non-ASCII Text",
RFC 2047, November 1996.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2234bis] [RFC2234bis]
Crocker, D. and P. Overell, "Augmented BNF for Syntax Crocker, D. and P. Overell, "Augmented BNF for Syntax
Specifications: ABNF", draft-crocker-abnf-rfc2234bis-00 Specifications: ABNF", draft-crocker-abnf-rfc2234bis-00
(work in progress), March 2005. (work in progress), March 2005.
[RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an [RFC2434] Narten, T. and H. Alvestrand, "Guidelines for Writing an
IANA Considerations Section in RFCs", BCP 26, RFC 2434, IANA Considerations Section in RFCs", BCP 26, RFC 2434,
October 1998. October 1998.
[RFC2781] Hoffman, P. and F. Yergeau, "UTF-16, an encoding of ISO
10646", RFC 2781, February 2000.
[RFC2860] Carpenter, B., Baker, F., and M. Roberts, "Memorandum of [RFC2860] Carpenter, B., Baker, F., and M. Roberts, "Memorandum of
Understanding Concerning the Technical Work of the Understanding Concerning the Technical Work of the
Internet Assigned Numbers Authority", RFC 2860, June 2000. Internet Assigned Numbers Authority", RFC 2860, June 2000.
[RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet: [RFC3339] Klyne, G. and C. Newman, "Date and Time on the Internet:
Timestamps", RFC 3339, July 2002. Timestamps", RFC 3339, July 2002.
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC [UN_M.49] Statistics Division, United Nations, "Standard Country or
Text on Security Considerations", BCP 72, RFC 3552,
July 2003.
[UN_M.49] Statistical Division, United Nations, "Standard Country or
Area Codes for Statistical Use", UN Standard Country or Area Codes for Statistical Use", UN Standard Country or
Area Codes for Statistical Use, Revision 4 (United Nations Area Codes for Statistical Use, Revision 4 (United Nations
publication, Sales No. 98.XVII.9, June 1999. publication, Sales No. 98.XVII.9, June 1999.
9.2 Informative References 9.2 Informative References
[RFC1766] Alvestrand, H., "Tags for the Identification of [RFC1766] Alvestrand, H., "Tags for the Identification of
Languages", RFC 1766, March 1995. Languages", RFC 1766, March 1995.
[RFC2047] Moore, K., "MIME (Multipurpose Internet Mail Extensions)
Part Three: Message Header Extensions for Non-ASCII Text",
RFC 2047, November 1996.
[RFC2231] Freed, N. and K. Moore, "MIME Parameter Value and Encoded [RFC2231] Freed, N. and K. Moore, "MIME Parameter Value and Encoded
Word Extensions: Character Sets, Languages, and Word Extensions: Character Sets, Languages, and
Continuations", RFC 2231, November 1997. Continuations", RFC 2231, November 1997.
[RFC2781] Hoffman, P. and F. Yergeau, "UTF-16, an encoding of ISO
10646", RFC 2781, February 2000.
[RFC3066] Alvestrand, H., "Tags for the Identification of [RFC3066] Alvestrand, H., "Tags for the Identification of
Languages", BCP 47, RFC 3066, January 2001. Languages", BCP 47, RFC 3066, January 2001.
[RFC3552] Rescorla, E. and B. Korver, "Guidelines for Writing RFC
Text on Security Considerations", BCP 72, RFC 3552,
July 2003.
[Unicode] Unicode Consortium, "The Unicode Consortium. The Unicode [Unicode] Unicode Consortium, "The Unicode Consortium. The Unicode
Standard, Version 4.1.0, defined by: The Unicode Standard, Standard, Version 4.1.0, defined by: The Unicode Standard,
Version 4.0 (Boston, MA, Addison-Wesley, 2003. ISBN 0-321- Version 4.0 (Boston, MA, Addison-Wesley, 2003. ISBN 0-321-
18578-1), as amended by Unicode 4.0.1 18578-1), as amended by Unicode 4.0.1
(http://www.unicode.org/versions/Unicode4.0.1) and by (http://www.unicode.org/versions/Unicode4.0.1) and by
Unicode 4.1.0 Unicode 4.1.0
(http://www.unicode.org/versions/Unicode4.1.0).", (http://www.unicode.org/versions/Unicode4.1.0).",
March 2005. March 2005.
[XML10] Bray (et al), T., "Extensible Markup Language (XML) 1.0", [XML10] Bray (et al), T., "Extensible Markup Language (XML) 1.0",
 End of changes. 

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