Do you know of any sources for the full language tags Code System? There are resources on the web like IETF.org that define the tag structure but it doesn’t provide a comprehensive list.
In relation to a list of language tags. That is almost impossible to maintain. IANA does maintain a database of language tags here: http://www.iana.org/assignments/language-subtag-registry
However, we regularly see comments like the following:
“Since it is impossible to list all the BCP 47 language tags and their combinations, we recommend compiling a list of the most commonly used language tags (defined using Language and Region subtags).”