Does 2e allow ISO 639-2 three-letter codes?

I would like to know whether the "Substantive" erratum
"E11" for XML 1.0 Second Edition [1] is intended to
license the use of three-letter language codes
as values for the xml:lang attribute, per the authority
of IETF RFC 3066 [2], Section "2.2 Language tag sources."

[ ] Yes
[ ] No

---------- Details/rationale --------

Given the instruction of the erratum to globally change
"[IETF RFC 1766] references to [IETF RFC 3066]", viz.,
change all occurrences of
<a http://www.w3.org/TR/2000/REC-xml-20001006#RFC1766">
[IETF RFC 1766]</a> to
<a http://www.w3.org/TR/2000/REC-xml-20001006#RFC1766">
[IETF RFC 3066]</a>, the last sentence of XML 1.0
Section 2.12, paragraph 1, would read:

   The values of the attribute are language
   identifiers as defined by [IETF RFC 3066],
   Tags for the Identification of Languages, or
   its successor on the IETF Standards Track.

While this statement (unqualified) should permit all
allowable RFC 3066 language codes, including ISO 639-2
three-letter codes, as values of xml:lang, the 'Note'
of Section 2.12 seems to (possibly) restrict the
values to two-letter language codes from ISO 639.

As amended, the remaining sentence of the Note reads:

  [IETF RFC 3066] tags are constructed from two-letter
  language codes as defined by [ISO 639]...

It is unclear whether this statement is (now) otiose,
deserving to be removed, so that there is unqualified
permission to all use all RFC 3066 codes, or
alternatively, whether this sentence has been retained
intentionally with the prescriptive meaning:

"In this context, the allowable IETF RFC 3066 tags shall
be only those constructed from the two-letter
language codes of ISO 639..."

Please note in this connection that

1) the references in the XML 1.0 Appendix do not cite
   ISO 639-2:1998 (nor DIS ISO 639-1)
   
2) the phrase of Section 2.12

   "...as defined by [IETF RFC 3066], Tags for the
   Identification of Languages, or its successor on
   the IETF Standards Track."

is curious because IETF RFC 3066 is not itself
(literally) on the "IETF Standards Track" as defined
by IETF.  It is assigned to "Category: Best Current
Practice" (thus also BCP: 47).  IETF RFC 1766 [3], which
is obsoleted by IETF RFC 3066, was however on the "IETF
Standards Track", assigned to "Category: Standards
Track."

Thank you for the clarification.

Robin Cover
XML Cover Pages
http://xml.coverpages.org

[1] http://www.w3.org/XML/xml-V10-2e-errata#E11
[2] http://www.ietf.org/rfc/rfc3066.txt
[3] http://www.ietf.org/rfc/rfc1766.txt

Received on Wednesday, 29 August 2001 10:51:41 UTC