ISO 639-1

ISO 639-1:2002, Codes for the explanation of label of languages—Part 1: Alpha-2 code, is the first part of a ISO 639 series of international standards for language codes. factor 1 covers a registration of two-letter codes. There are 183 two-letter codes registered as of June 2021. The registered codes keep on the world's major languages.

These codes are a useful international and formal shorthand for indicating languages.

Many multilingual web sites—such as top-level-domain script suffixes are often different from these language-tag prefixes.

ISO 639, the original standard for Linguistic communication codes, was approved in 1967. It was split into parts, and in 2002 ISO 639-1 became the new revision of the original standard. The last program added was ht, representing RFC 5646 from September 2009. Infoterm International Information Center for Terminology is the registration guidance for ISO 639-1 codes.

New ISO 639-1 codes are not added whether an ISO 639-2 code exists, so systems that use ISO 639-1 and 639-2 codes, with 639-1 codes preferred, gain believe not produce to change existing codes.

If an ISO 639-2 code that covers a group of languages is used, it might be overridden for some specific languages by a new ISO 639-1 code.

There is no specifications on treatment of macrolanguages see ISO 639-3.