As recommended by David I'm reposting part of my previous mail under a more appropriate subject.
You should use simple language codes when there is no need for spcifying country, or to differentiate between different country varieties. AFAIK there are no country varieties of Asturian, it is thus probably best to
rename "ast_ES" to "ast", as ast_ES is a more specific code than necessary. This can be a real problem with language detection. F. ex. if you set Portuguese on the top of your language list in Chromium you will not be given the Portuguese version when you visit
maposmatic.org because Chromium asks for "pt" and we can only offer "pt_BR". For Brazilian Portuguese this might be the intention, but for languages where there are no real country variety it just makes the chance of things going wrong higher. (It is not a problem the other way around. Try setting your Chromium language to "German - Austria", although maposmatic does not have an "de_AT" language, you'll still be given the "de" translation").
As long as there are no "pt_PT" and "nl_BE" translations, I also think "pt_BR" and "nl_NL" should be renamed to "pt" and "nl" respectively and "tr_TR" should definitely be renamed to "tr".