[Bug 17864] i18n-ISSUE-118: explicitly undefined language

https://www.w3.org/Bugs/Public/show_bug.cgi?id=17864

--- Comment #2 from Addison Phillips <addison@lab126.com> 2012-09-28 18:20:18 UTC ---
(In reply to comment #1)
> (The other bugs I had in mind don't cover this specific issue.)
> 
> Addison: What effect would it have if lang="und"? Where is that defined? I'll
> try to use the same language. (I don't want to explicitly make them equivalent,
> because the unknown codes have to be passed through to CSS, OpenType, etc.)

I see lang="und" as being slightly different from lang="", although BCP 47
makes them equivalent in meaning. 'und' is defined by ISO 639-2 and is
incorporated along with 'zxx', 'mul', and 'mis'. The specific definitions are
here:

  http://tools.ietf.org/html/bcp47#section-4.1

See item #5, which has this sub-bullet about 'und':

       *  The 'und' (Undetermined) primary language subtag identifies
          linguistic content whose language is not determined.  This
          subtag SHOULD NOT be used unless a language tag is required
          and language information is not available or cannot be
          determined.  Omitting the language tag (where permitted) is
          preferred.  The 'und' subtag might be useful for protocols
          that require a language tag to be provided or where a primary
          language subtag is required (such as in "und-Latn").  The
          'und' subtag MAY also be useful when matching language tags in
          certain situations.

The way I see lang="und" being different from lang="" is probably the same
thing you allude to you in your comment: there is actually a value there and,
as far as any HTML processor is aware, it might contain some meaning or be
available for matching. The processor would have to look at the content of the
attribute and determine that it is 'und' in order to determine the
"undetermined-ness" of the language, which is something we want to avoid.
Hence: the 'und' tag should not be used in HTML5 (although it is not illegal to
do so) because HTML5/HTML-next allows the empty string.

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Received on Friday, 28 September 2012 18:20:20 UTC