Codes for constructed languages
This is a list of ISO 639 codes and IETF language tags for individual constructed languages, complete as of 2023.
ISO 639-2 and ISO 639-5 also have the code for artificial languages. The BCP 47 subtag can be used to create a suitable private use tag for any constructed language that has not been assigned an official language tag.
The old SIL language identifiers are officially obsolete and should no longer be used. They formed the basis of the ISO 639-3 language codes, but some SIL identifiers that had been retired before the establishment of ISO 639-3 were later assigned to different languages within ISO.
The IANA Language Subtag Registry was updated on 29 July 2009 to include all ISO 639-3 and ISO 639-5 identifiers in use at that time.