odf 1.1 dc:language value (unchanged as yet for 1.2)

The manner in which the language is represented is similar to the
language tag described in [RFC3066].

yet the schema calls up relax NG 'language' data type.
http://www.w3.org/TR/xmlschema-2/#language

language represents natural language identifiers as defined by by [RFC
3066] . The ·value space· of language is the set of all strings that
are valid language identifiers as defined [RFC 3066] . The ·lexical
space· of language is the set of all strings that conform to the
pattern [a-zA-Z]{1,8}(-[a-zA-Z0-9]{1,8})* . The ·base type· of
language is token.

Is it valid to RFC3066 or 'similar' to?

What's the conformance requirement for this para?

regards

-- 
Dave Pawson
XSLT XSL-FO FAQ.
http://www.dpawson.co.uk