ISO 639-1

ISO 639-1 is part of the international standard ISO 639, which assigns short codes to languages so that computers and information systems can distinguish them. ISO 639-1 codes consist of two Latin characters, for example so (Somali), en (English), ar (Arabic), fr (French).

Because only two characters can be combined in roughly 700 different ways, ISO 639-1 covers only a limited number of major languages or those widely used in writing and publishing. Other languages are covered by other parts of the standard, particularly ISO 639-2 and ISO 639-3, which use three characters and cover a much larger number of languages.

Structure of codes

Each code consists of two lowercase letters in standard notation. A code represents a language, not a country or nationality. For example, de stands for German (Deutsch), which is used in several countries where German is spoken. When regional varieties need to be distinguished, the language code is combined with the country code from ISO 3166-1, such as pt-BR (Brazilian Portuguese) or en-GB (British English).

Relationship to other parts of ISO 639

ISO 639-2 provides three-character codes, sometimes in two forms: one for bibliographic purposes and one for terminology. ISO 639-3 expanded the system to cover roughly all known languages, including minority and endangered ones. Every language with an ISO 639-1 code also has a three-character code; for example, so corresponds to som.

Uses

ISO 639-1 is widely used on the internet and in software: setting language preferences on news websites, Wikipedia domain names (for example so.wikipedia.org), metadata for books and databases, and translation systems. It also serves as the basis for language codes in internet standards that specify the language of a document.