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.
Table of Contents
1. Introduction ....................................................2
2. Initialization of the Registry ..................................2
3. Initial Registry Contents .......................................5
4. Omitted Code Elements ...........................................5
5. Security Considerations .........................................5
6. IANA Considerations .............................................5
7. References ......................................................6
7.1. Normative References .......................................6
7.2. Informative References .....................................6
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1. 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.
2. 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
Ewell Informational [Page 2]RFC 4645 Initial Language Subtag Registry September 2006
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
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"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.
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3. 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".
4. 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.
5. 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].
6. 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].
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7. References
7.1. Normative References
[RFC4646] Phillips, A., Ed. and M. Davis, Ed., "Tags for
Identifying Languages", BCP 47, RFC 4646, September
2006.
7.2. 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: dewell@adelphia.net
URI: http://users.adelphia.net/~dewell
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