ISO 639 is a standardized nomenclature used to classify all known languages. Each language is assigned a two-letter (639-1) and three-letter (639-2 and 639-3), lowercase abbreviation, amended in later versions of the nomenclature. The system is highly useful for linguists and ethnographers to categorize the languages spoken on a regional basis, and to compute analysis in the field of lexicostatistics.

• ISO 639-1 two-letter codes, one per language or ISO 639 macrolanguage
• ISO 639-2 three-letter codes, for the same languages as 639-1
• ISO 639-3 three-letter codes, the same as 639-2 for languages, but with distinct codes for each variety of an ISO 639 macrolanguage

Official web site for ISO 639
Official ISO 639 list

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