Codes for constructed languages
This is a list of ISO 639 codes and IETF language tags (BCP 47) for individual constructed languages, complete as of November 2009.
ISO 639-2 and ISO 639-5 also have the code art for other artificial languages. BCP 47 similarly has the subtag art, which together with the subtag x can be used to create a suitable private use tag for any constructed language that has not been assigned an official language tag (e.g., art-x-solresol could be used for Solresol, or art-x-Latino-sine-flexione for Latino sine flexione).