Get all languages

[weeco]

Hello,
I am working on a translation management system and therefore I need all available languages and it's ISO codes. However this list var languageList = languages.all contains entries like:

alpha2=, alpha3=zxx, bibliographic=, name=No linguistic content

alpha2=, alpha3=zxx, bibliographic=, name=Not applicable

alpha2=, alpha3=und, bibliographic=, name=Undetermined

alpha2=, alpha3=gmh, bibliographic=, name=German, Middle High (ca.1050-1500)

All these entries are obviously very irrelevant for my purpose. Instead I want to get English (USA), English (GB) and such. Is there a way to get only the official languages including differences like American vs British English?

[weeco]

Basically I am looking for the ISO 639-1 languages: http://www.andiamo.co.uk/resources/iso-language-codes