Deprecating Unicode Language Tag Characters: RFC 2482 is Historic
Moving an outdated Unicode feature from standards to history.
Whistler, K., Adams, G., Duerst, M., Presuhn, R., Ed., and J. Klensin, "Deprecating Unicode Language Tag Characters: RFC 2482 is Historic", RFC 6082, DOI 10.17487/RFC6082, November 2010, <https://www.rfc-editor.org/info/rfc6082>.
@misc{rfc6082,
series = {Request for Comments},
number = 6082,
howpublished = {RFC 6082},
publisher = {RFC Editor},
doi = {10.17487/RFC6082},
url = {https://www.rfc-editor.org/info/rfc6082},
author = {K. Whistler and G. Adams and M. Duerst and R. Presuhn and J. Klensin},
title = {{Deprecating Unicode Language Tag Characters: RFC 2482 is Historic}},
pagetotal = 4,
year = 2010,
month = nov,
} RFC text
Contents
Internet Engineering Task Force (IETF) K. Whistler
Request for Comments: 6082 Sybase, Inc.
Obsoletes: 2482 G. Adams
Category: Informational Skynav (Phil), Inc.
ISSN: 2070-1721 M. Duerst
Aoyama Gakuin University
R. Presuhn, Ed.
J. Klensin
November 2010
Deprecating Unicode Language Tag Characters: RFC 2482 is Historic
Abstract
RFC 2482, "Language Tagging in Unicode Plain Text", describes a
mechanism for using special Unicode language tag characters to
identify languages when needed without more general markup such as
that provided by XML. The Unicode Consortium has deprecated that
facility and strongly recommends against its use. RFC 2482 has been
moved to Historic status to reduce the possibility that Internet
implementers would consider that system an appropriate mechanism for
identifying languages.
Status of This Memo
This document is not an Internet Standards Track specification; it is
published for informational purposes.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Not all documents
approved by the IESG are a candidate for any level of Internet
Standard; see Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc6082.
Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Table of Contents
1. Introduction ....................................................2
2. Action ..........................................................2
3. Security Considerations .........................................3
4. Acknowledgments .................................................3
5. References ......................................................3
5.1. Normative References .......................................3
5.2. Informative References .....................................3
1. Introduction
RFC 2482, "Language Tagging in Unicode Plain Text" [RFC2482],
describes a mechanism for using special Unicode language tag
characters to identify languages when needed. It is an idea whose
time never quite came. It has been superseded by whole-transaction
language identification such as the MIME Content-language header
[RFC3282] and more general markup mechanisms such as those provided
by XML. The Unicode Consortium has deprecated the language tag
character facility and strongly recommends against its use. RFC 2482
has been moved to Historic status to reduce the possibility that
Internet implementers would consider that tagging system an
appropriate mechanism for identifying languages.
A discussion of the status of the language tag characters and their
applicability appears in Section 16.9 of The Unicode Standard
[Unicode52].
2. Action
RFC 2482 has been deprecated and reclassified as Historic. Internet
protocols and Standards-Track documents should not use the facilities
described in that document.
3. Security Considerations
By deprecating RFC 2482, we eliminate a facility that is no longer
encouraged or supported by the Unicode Consortium and that may have
been slightly risky in use if misinterpreted or if expectations of
support were not met. So, if this action has any effect on Internet
security at all, it should be positive.
4. Acknowledgments
Helpful comments were received from Peter Koch and S. Moonesamy.
5. References
5.1. Normative References
[RFC2482] Whistler, K. and G. Adams, "Language Tagging in Unicode
Plain Text", RFC 2482, January 1999.
[Unicode52] The Unicode Consortium. The Unicode Standard, Version
5.2.0, defined by: "The Unicode Standard, Version
5.2.0", (Mountain View, CA: The Unicode Consortium,
2009. ISBN 978-1-936213-00-9).
<http://www.unicode.org/versions/Unicode5.2.0/>.
5.2. Informative References
[RFC3282] Alvestrand, H., "Content Language Headers", RFC 3282,
May 2002.
Authors' Addresses
Kenneth Whistler
Sybase, Inc.
One Sybase Dr.
Dublin, CA 94568
USA
Phone: +1 925 236 7429
EMail: kenw@sybase.com
Glenn Adams
Skynav (Phil), Inc.
Lot 14 Boton Area
Subic Bay Freeport Zone 2222
Philippines
Phone:
EMail: glenn@skynav.com
Martin Duerst
Aoyama Gakuin University
5-10-1 Fuchinobe
Sagamihara, Kanagawa 229-8558
Japan
Phone: +81 42 759 6329
Fax: +81 42 759 6495
EMail: duerst@it.aoyama.ac.jp
Randy Presuhn (editor)
San Jose, CA 95120
USA
Phone:
EMail: randy_presuhn@mindspring.com
John C Klensin
1770 Massachusetts Ave, Ste 322
Cambridge, MA 02140
USA
Phone: +1 617 245 1457
EMail: john+ietf@jck.com
AI ELI5
On this page
§1Why RFC 2482 is Being Deprecated
RFC 2482 proposed a mechanism for embedding special Unicode language tag characters into plain text to identify which language the text was written in. The idea was to enable language identification without requiring markup like XML.
The Unicode Consortium—the organization that maintains the Unicode Standard—has now deprecated this facility. They found that whole-message language identification (such as MIME Content-Language headers) and general markup mechanisms (such as XML) proved more practical. The language tag character approach was an idea whose time never quite came.
A way to mark text's language with invisible characters didn't work well in practice, so it was retired.
§2The Action Taken
RFC 2482 has been reclassified as Historic. This designation means that Internet protocols and Standards-Track documents should no longer use the facilities it describes. The change removes an outdated mechanism from consideration and steers protocol designers toward better alternatives already in use.
The old note is moved to a 'historic' pile so new protocols won't accidentally use the broken approach.
§3Security Implications
Deprecating RFC 2482 has a net positive security effect. The language tag character facility was no longer encouraged or supported by the Unicode Consortium, and it could have posed a slight risk if misinterpreted or if implementations had unsupported expectations of how it would work. Removing it eliminates that source of confusion and misconfiguration.
Getting rid of the old, unsupported approach makes systems safer because people won't get confused trying to use something that doesn't really work.