ISO 639 is the International Standard for language codes. The purpose of ISO 639 is to establish internationally recognised codes (either 2, 3, or 4 letters long) for the representation of languages or language families.
Uses of ISO 639
These codes are widely used in many different disciplines, for example for bibliographic purposes, in the library community, as well as for computerized systems, and the representation of different language versions on websites.
Using a code rather than the name of a language has many benefits as some languages are referred to by different groups in different ways, and two unrelated languages may share the same or similar name.
ISO 639 is composed of five different parts
- Part 1 (ISO 639-1:2002) provides a 2 letter code that has been designed to represent most of the major languages of the world.
- Part 2 (ISO 639-2:1998) provides a 3 letter code, which gives more possible combinations, so ISO 639-2:1998 can cover more languages.
- Part 3 (ISO 639-3:2007) provides a 3 letter code and aims to give as complete a listing of languages as possible, including living, extinct and ancient languages.
- Part 4 (ISO 639-4:2010) gives the general principles of language coding and lays down guidelines for the use of ISO 639.
- Part 5 (ISO 639-5:2008) provides a 3 letter code for language families and groups (living and extinct).
The language codes are open lists that can be extended and refined. The job of maintaining these standards has been given to bodies known as Registration Authorities.
Details of the Registration Authorities for ISO 639 can be found in the list of Registration Authorities and Maintenance Agencies.