Criteria for languages?

John Cowan cowan at
Wed Dec 2 18:11:33 CET 2009

Peter Constable scripsit:

> A further question: for those that want to tag content specifically
> as Standard Latvian, do we recommend "lvs" or "lav-lvs"? It takes a
> bit of reading in RFC5646 to figure out the answer. The first clue is
> this from section 2.2.2:

"lvs" is the only option.  Only the seven macrolanguages 'ar', 'kok',
'ms', 'sw', 'uz', and 'zh', plus the pseudo-macrolanguage 'sgn', are
allowed to be prefixes for extlang tags, per Section 3.4, rule 12.C.2.

            2.  'Extlang' records SHOULD NOT be created for languages if
                other languages encompassed by the macrolanguage do not
                also include 'extlang' records.  For example, if a new
                Serbo-Croatian ('sh') language were registered, it would
                not get an extlang record because other languages
                encompassed, such as Serbian ('sr'), do not include one
                in the registry.

Technically, that's a SHOULD NOT rather than a MUST NOT, so we could add
"lvs" (and presumably "ltg") as extlang subtags, but (per RFC 2116):

   [T]here may exist valid reasons in particular circumstances when the
   particular behavior is acceptable or even useful, but the full
   implications should be understood and the case carefully weighed
   before implementing any behavior described with this label.

I haven't seen any argument to that effect.

John Cowan   <cowan at>
    "Any legal document draws most of its meaning from context.  A telegram
    that says 'SELL HUNDRED THOUSAND SHARES IBM SHORT' (only 190 bits in
    5-bit Baudot code plus appropriate headers) is as good a legal document
    as any, even sans digital signature." --me

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