ISO 639-2 language codes

An extended version of the LOC Codes that has the current Terminology Alpha-3 code for each language, such as 'deu' for German as skos:notation and for languages that have differing codes in the Bibliographic Scheme (B) it contains this code as a second skos:notation with the datatype 'zpid:bcode'.

http://www.w3.org/2004/02/skos/core#ConceptScheme

http://id.loc.gov/vocabulary/iso639-2/

https://w3id.org/zpid/vocabs/langcodes