RFC4645
Network Working Group D. Ewell, Ed. Request for Comments: 4645 Consultant Category: Informational September 2006
Initial Language Subtag Registry
Status of This Memo
This memo provides information for the Internet community. It does not specify an Internet standard of any kind. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
This memo defined the initial contents of the IANA Language Subtag Registry for use in forming tags for the identification of languages. Since the contents of this memo only served as a starting point for the registry, its actual contents have been removed before publication to avoid confusion.
Contents
Introduction
RFC4646 provides for a Language Subtag Registry and describes its format. This memo defines the initial contents of the IANA Language Subtag Registry, using the criteria described in Section 2.
The Language Subtag Registry is formatted in a modified record-jar text format, as described in [record-jar]. The specific format of the registry, and the definition and intended purpose of each of the fields, are described in RFC4646.
The registry is expected to change over time, as new subtags are registered and existing subtags are modified or deprecated. The process of updating the registry is described in Section 3 of RFC4646. This memo does not define the permanent contents of the registry and should not be represented as doing so.
Many of the subtags defined in this registry are based on code elements defined in [ISO639-1], [ISO639-2], [ISO15924], [ISO3166-1], and [UN_M.49]. This registry is not a mirror of the code lists defined by these standards and should not be used as one.
Initialization of the Registry
Section 3.7 of RFC4646 requires that the LTRU working group create an initial version of the Language Subtag Registry and populate it with the initial set of subtags. This involves converting the entries from the existing IANA language tag registry defined by RFC3066 to the new format, as well as defining valid subtags from various source standards. This section describes the process that was used to create the initial registry entries.
The initial set of records was based on the following standards: [ISO639-1], [ISO639-2], [ISO15924], and [ISO3166-1]. The following criteria were used to select and format the records of the subtags included in the initial Language Subtag Registry (hereafter "ILSR"):
1. For each source standard, the date of the standard referenced
in RFC1766 was selected as the starting date. Code elements
that were valid on that date in the selected standard were
added to the ILSR. Code elements that were previously
assigned, but that were vacated or withdrawn before that date,
were not added to the ILSR.
2. For each successive change to the standard, any additional
assignments up to the date of the adoption of RFC4646 were
added to the ILSR. Values that have been withdrawn are marked
as deprecated, but not removed. Changes in meaning or
assignment of a subtag were permitted during this process (for
example, the [ISO3166-1] code element 'CS' was originally
assigned to Czechoslovakia and is now assigned to Serbia and
Montenegro).
Code elements from [UN_M.49] were also included in the ILSR using the criteria above, with the following additional rules:
3. UN numeric code elements assigned to "macro-geographical
(continental)" regions as of the date of adoption of RFC4646
were added to the ILSR and thereby made valid for use in
language tags.
4. The UN numeric code elements for "economic groupings" or
"other groupings," and the alphanumeric code elements in
Appendix X of the UN document, were not added to the ILSR.
5. The UN numeric code elements for countries or areas not
associated with an assigned [ISO3166-1] alpha-2 code element
were not added to the ILSR. These values are listed in
Section 4 and may be requested for registration by individuals
using the process defined in RFC4646 and according to the
rules described therein. Listing of these code elements in
this section is not a guarantee of future registration.
6. Code elements that were withdrawn, vacated, or deprecated from
[UN_M.49] as of the date of adoption of RFC4646 were not
added to the ILSR.
Using the initial set of subtags described above, the tags in the RFC3066 registry were evaluated as follows:
7. Tags in the RFC3066 registry that were not deprecated, consisted entirely of subtags already in this document, and have the correct form and format for tags defined by RFC4646 were converted to records of type "redundant" in the ILSR. For example, "zh-Hant" is now defined by RFC4646 because 'zh' is an [ISO639-1] code element and 'Hant' is an [ISO15924] code element, and both are defined as subtags in the ILSR.
8. Tags in the RFC3066 registry that contained one or more subtags that either did not match the valid registration pattern or were not otherwise defined by RFC4646 were converted to corresponding records of type "grandfathered" in the ILSR. These records cannot become type "redundant" except by revision of RFC4646, but may have a "Deprecated" and
"Preferred-Value" field added to them if a subsequent subtag
assignment or combination of assignments renders the tag
obsolete.
9. Tags in the RFC3066 registry that had a notation that they were deprecated were converted to records of type "grandfathered" in the ILSR. The record for the grandfathered entry contains a "Deprecated" field with the most appropriate date that can be determined for when the RFC3066 record was deprecated. The "Comments" field may optionally contain a reason for the deprecation. The "Preferred-Value" field contains a tag that replaces the value. For example, the RFC3066 tag "art-lojban" is deprecated and thus appears as a grandfathered tag in the ILSR. Its "Deprecated" field contains the deprecation date (in this case "2003-09-02") and the "Preferred-Value" field the value "jbo".
10. The remaining tags in the RFC3066 registry are not deprecated and have a format consistent with language tags as defined by RFC4646 but contain subtags that are not defined in the ILSR. These subtags are eligible for registration as variants. The ILSR contains appropriate variant records for the following list of subtags, and the registered RFC3066 tags containing these subtags were entered into the ILSR as type "redundant":
1901 (use with Prefix: de)
1996 (use with Prefix: de)
nedis (use with Prefix: sl)
rozaj (use with Prefix: sl)
11. All remaining RFC3066 registered tags were converted to records of type "grandfathered" in the ILSR. Interested parties may use the registration process in RFC4646 to attempt to register the variant subtags not already present in the Language Subtag Registry. If all of the subtags in the original tag become fully defined by the resulting registrations, then the original tag is superseded. Such tags will have their record changed from type "grandfathered" to type "redundant" in the registry. Note that previous approval of a tag under RFC3066 is not a guarantee of approval of a variant subtag under RFC4646. The existing RFC3066 tag maintains its validity, but the original reason for its registration might have become obsolete.
Initial Registry Contents
The remainder of this section specified the initial set of records for the registry. This material was deleted on publication of this memo, to avoid any potential confusion with the registry itself. The IANA language subtag registry can be found at <http://www.iana.org/numbers.html> under "Language Tags".
Omitted Code Elements
The following code elements from [UN_M.49] were not associated with [ISO3166-1] alpha-2 code elements. Consequently, they were not assigned as subtags in the initial Language Subtag Registry, but were valid candidates for registration as region subtags, using the process in RFC4646:
830 Channel Islands 831 Guernsey 832 Jersey 833 Isle of Man
The last three became ineligible for registration in April, 2006, when the [ISO3166-1] code elements GG, JE, and IM were assigned as region subtags.
Security Considerations
This document specifies the initial contents to be used by IANA in populating the Language Subtag Registry. For security considerations relevant to that registry and the use of language tags, see RFC4646.
IANA Considerations
This document points to the initial content for the Language Subtag Registry which is maintained by the IANA. The IANA language subtag registry can be found at <http://www.iana.org/numbers.html> under "Language Tags". For details on the procedures for the format and ongoing maintenance of this registry, see RFC4646.
References
Normative References
RFC4646 Phillips, A., Ed. and M. Davis, Ed., "Tags for
Identifying Languages", BCP 47, RFC 4646, September 2006.
Informative References
[ISO15924] International Organization for Standardization, "ISO
15924:2004. Information and documentation -- Codes for
the representation of names of scripts", January 2004.
[ISO3166-1] International Organization for Standardization, "ISO
3166:1988. Codes for the representation of names of
countries, 3rd edition", August 1988.
[ISO639-1] International Organization for Standardization, "ISO
639-1:2002. Codes for the representation of names of
languages -- Part 1: Alpha-2 code", 2002.
[ISO639-2] International Organization for Standardization, "ISO
639-2:1998. Codes for the representation of names of
languages -- Part 2: Alpha-3 code, first edition",
1998.
RFC1766 Alvestrand, H., "Tags for the Identification of
Languages", RFC 1766, March 1995.
RFC3066 Alvestrand, H., "Tags for the Identification of
Languages", BCP 47, RFC 3066, January 2001.
[UN_M.49] Statistics Division, United Nations, "Standard Country
or Area Codes for Statistical Use", UN Standard Country
or Area Codes for Statistical Use, Revision 4 (United
Nations publication, Sales No. 98.XVII.9, June 1999.
[record-jar] Raymond, E., "The Art of Unix Programming", 2003.
Author's Address
Doug Ewell (Editor) Consultant
EMail: [email protected] URI: http://users.adelphia.net/~dewell
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