ISO 639-2:1998, Codes for the representation of names of languages — Part 2: Alpha-3 code, is the second part of the ISO 639 standard, which lists codes for the representation of the names of languages. The three-letter codes given for each language in this part of the standard are referred to as "Alpha-3" codes. There are 464 entries in the list of ISO 639-2 codes.

Applicable codes in this context include

Special codes in ISO 639-2:

  • und undetermined (language)
  • mis uncoded language
  • mul multiple languages
  • zxx no linguistic content, not applicable

More information and a full list on the Wikipedia page [1]. The Library of Congress page is [2d4chanfag]