doug at ewellic.org
Tue Jan 21 06:47:45 CET 2014
One of the readily available test suites for BCP 47 tags shows "fr-fra"
and "fr-Lat" as valid tags. They aren't, of course, because Section
> A tag is considered "valid" if it satisfies these conditions:
> o The tag is well-formed.
> o Either the tag is in the list of grandfathered tags or all of its
> primary language, extended language, script, region, and variant
> subtags appear in the IANA Language Subtag Registry as of the
> particular registry date.
> o There are no duplicate variant subtags.
> o There are no duplicate singleton (extension) subtags.
and the extended language subtags 'fra' and 'lat' do not appear in the
Registry (nor could they ever).
I was surprised, however, to see that a combination of language and
extlang subtags that don't match -- that is, the language is not the
Prefix for the extlang, as "ar-cmn" -- is perfectly valid. In fact, the
language subtag in such a pair doesn't even have to have its own
extlangs, so one could also write "fr-cmn" or "tlh-cmn" and a validating
processor would have to accept them. Does this surprise anyone else?
Doug Ewell | Thornton, CO, USA
http://ewellic.org | @DougEwell
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