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[802SEC] FW: [New-work] WG Review: Language Tag Registry Update (ltru)

The following announcement may be of interest to members of your working


-----Original Message-----
From: [] On
Behalf Of The IESG
Sent: Thursday, February 24, 2005 11:11 AM
Subject: [New-work] WG Review: Language Tag Registry Update (ltru)

A new IETF working group has been proposed in the Applications Area.
The IESG has not made any determination as yet. The following
description was submitted, and is provided for informational purposes
only. Please send your comments to the IESG mailing list (
by March 2nd.


Language Tag Registry Update (LTRU)

Current Status: Proposed Working Group

Description of Working Group:

RFC 3066 and its predecessor, RFC 1766, defined language tags for use on
the Internet. Language tags are necessary for many applications, ranging
from cataloging content to computer processing of text. The RFC 3066
standard for language tags has been widely adopted in various protocols
and text formats, including HTML, XML, and CLDR, as the best means of
identifying languages and language preferences.  Since the publication
of RFC 3066, however, several issues have faced implementors of language

    * Stability and accessibility of the underlying ISO standards
    * Difficulty with registrations and their acceptance
    * Lack of clear guidance on how to identify script and region where
    * Lack of parseability and the ability to verify well-formedness.
    * Lack of specified algorithms, apart from pure prefix matching,
      for operations on language tags.

This working group will address these issues by developing two
documents. The first is a successor to RFC 3066.  It will describe the
structure of the IANA registry and how the registered tags will relate
to the generative mechanisms (originally described in RFC 3066, but
likely to be updated by the document).  In order to be complete, it will
need to address each of the challenges set out above:

- For stability, it is expected that the document will describe how the
meaning of language tags remains stable, even if underlying references
should change, and how the structure is to remain stable in the future.
For accessibility, it is to provide a mechanism for easily determining
whether a particular subtag is valid as of a given date, without onerous
reconstruction of the state of the underlying standard as of that time.

- For extensibility, it is expected that the document will describe how
generative mechanisms could use ISO 15924 and UN M.49 codes without
explicit registration of all combinations. The current registry contains
pairs like uz-Cyrl/uz-Latn and sr-Cyrl/sr-Latn, but RFC 3066 contains no
general mechanism or guidance for how scripts should be incorporated
into language tags; this replacement document is expected to provide
such a mechanism.

- It is also expected to provide mechanisms to support the evolution of
the underlying ISO standards, in particular ISO 639-3, mechanisms to
support variant registration and formal extensions, as well as allowing
generative private use when necessary.

- It is expected to specify a mechanism for easily identifying the role
of each subtag in the language tag, so that, for example, whenever a
script code or country code is present in the tag it can be extracted,
even without access to a current version of the registry. Such a
mechanism would clearly distinguish between well-formed and valid
language tags, to allow for maximal compatibility between
implementations released at different times, and thus using different
versions of the registry.

The second document will describe matching algorithms for use with
language tags.  Language tags are used in a broad variety of contexts
and it is not expected that any single matching algorithm will fit all
needs.  Developing a small set of common matching and sorting algorithms
does seem likely to contribute to interoperability, however, as it seems
likely that using protocols could reference these well-known algorithms
in their specifications.

This working group will not take over the existing review function of
the ietf-languages list.  The ietf-languages list will continue to
review tags according to RFC 3066 until the first document produced by
the WG is finished.  Then it will review according to whatever
procedures the first document specifies.

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