Language Identifier List Criteria

[Georg Schweizer]

> Some languages are spoken in many countries, and the language is not 
> distinctive in each country. I have started to accept suggestions as 
> to which language-region codes do not represent a distinct language 
> variation, and therefore are not recommended as tags, without good 
> reason.
http://www.i18nguy.com/unicode/language-identifiers.html

The criteria should be political rather than linguistic ones, as both 
the ISO 639 language tags and the ISO 3166 country codes are based on 
political agreement. Therefore I would not speak of "distict language 
variations", but of distinct *official standards* (or at least distinct 
conventions). Variations can be found everywhere (even within one 
political region), whereas the same conventions can be followed by 
several countries.