ISO 639

ISO 639 is the set of international standards that lists short codes for language names. It was also the name of the original standard, approved in 1967 and withdrawn in 2002.

ISO 639 consists of different parts, of which two parts have been approved and a third part that is in the final approval (FDIS) stage. The other parts are works in progress.

*ISO 639-1: 2002 "Codes for the representation of names of languages -- Part 1: Alpha-2 code"; List of ISO 639-1 codes
*ISO 639-2: 1998 "Codes for the representation of names of languages -- Part 2: Alpha-3 code"; List of ISO 639-2 codes
*ISO 639-3: 2007 "Codes for the representation of names of languages -- Part 3: Alpha-3 code for comprehensive coverage of languages"; List of ISO 639-3 codes
*ISO/CD 639-4: 2008? "Codes for the representation of names of languages -- Part 4: Implementation guidelines and general principles for language coding"
*ISO 639-5: 2008 "Codes for the representation of names of languages -- Part 5: Alpha-3 code for language families and groups"; May 15, 2008
*ISO/CD 639-6: 2008? "Codes for the representation of names of languages -- Part 6: Alpha-4 representation for comprehensive coverage of language variation"

Use of ISO 639 codes

The language codes defined in the several sections of ISO 639 are used for bibliographic purposes and, in computing and internet environments, as a key element of locale data. The codes also find use in various applications, such as Wikipedia URLs for its different language editions.

Alpha-2 code space

"Alpha-2" codes (for codes composed of 2 letters of the basic Latin alphabet) are used in ISO 639-1. When codes for a wider range of languages were desired, more than 2 letter combinations could cover (a maximum of $26^2=676$), ISO 639-2 was developed using Alpha-3 codes (though the latter was formally published first).Fact|date=August 2008

Alpha-3 code space

"Alpha-3" codes (for codes composed of 3 letters of the basic Latin alphabet) are used in ISO 639-2, ISO 639-3, and ISO 639-5. Mathematically, the upper limit for the number of languages and language collections that can be so represented is $26^3=17,576$.

The common use of Alpha-3 codes by three parts of ISO 639 requires some coordination within a larger system.

Part 2 defines four special codes mul, und, mis, zxx, a reserved range qaa-qtz (20 × 26 = 520 codes) and has 23 double entries (the B/T codes). This sums up to 520 + 23 + 4 = 547 codes that cannot be used in part 3 to represent languages or in part 5 to represent language families or groups.The remainder is 17,576 – 547 = 17,029.

There are somewhere around six or seven thousand languages on Earth today [http://en.wikipedia.org/wiki/List_of_endangered_languages] [http://www.ethnologue.com/ethno_docs/distribution.asp?by=family] . So those 17,029 codes are adequate to assign a unique code to each language, although some languages may end up with arbitrary codes that sound nothing like traditional name(s) of that language.

Alpha-4 code space

"Alpha-4" codes (for codes composed of 4 letters of the basic Latin alphabet) is proposed to be used in ISO 639-6. Mathematically, the upper limit for the number of languages and dialects that can be so represented is $26^4=456,976$.

ee also

* IETF language tags (based on ISO 639)
* ISO 3166 (codes for countries)
* ISO 15924 (codes for writing systems)
* language code
* language families and languages
* list of ISO 639-1 codes
* list of ISO 639-2 codes
* list of ISO 639-3 codes
* list of languages
* list of official languages

External links

* [http://www.bsi-global.com British Standards Institute]
* [http://www.loc.gov/standards/iso639-2/ ISO 639-2 Registration Authority]
* [http://www.sil.org/iso639-3/ ISO 639-3 Registration Authority]
* [http://www.ethnologue.com/iso639/ ISO 639 and the Ethnologue]
* [http://web.archive.org/web/20071129183244/http://www.niso.org/international/SC4/N585.pdf ]
* [http://fara.cs.uni-potsdam.de/~georgk/639.xml XML version] of the official ISO 639-2 HTML data from the Library of Congress
* [http://www.prato.linux.it/~lmasetti/seriamente/index.php?sez=materiali&subsect=iso639 Language codes in English and Italian] with Perl scripts for parsing and PHP code