ISO 639 is a standard by the International Organization for Standardization (ISO) concerned with the representation of languages and language groups. It currently consists of four sets (1–3, 5) of code, named after each part which formerly described respective set (part 4 was guidelines without its own coding system); a part 6 was published but withdrawn. It was first approved in 1967 as a single-part ISO Recommendation, ISO/R 639, superseded in 2002 by part 1 of the new series, ISO 639-1, followed by additional parts. All existing parts of the series were consolidated into a single standard in 2023, largely based on the text of ISO 639-4.
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.
History The early form of ISO's language coding system was manifested by ISO/R 639:1967 titled Symbols for Languages, Countries and Authorities, which aimed chiefly to regulate vocabularies signifying languages, countries, and standardization agencies of ISO member bodies. Its "language symbols" consisted of one- or two-letter variable-length identifiers in capitalized Latin alphabets, e.g. E or En for English; S, Sp, or Es for Spanish; and In for Indonesian. It was also allowed to use (the pre-1993 version of) UDC numeral auxiliaries to indicate languages.
List of language symbols in ISO/R 639:1967 Name (English) 1-letter 2-letter UDC (1988) (Current Set 1) Afrikaans — Af =393.6 af af Arabic — Ar =927 ar ar Bulgarian — Bg =867 bg bg Chinese C Ch =951 zh zh Czech — Cs =850 cs cs German D De =30 de de Danish — Da =398 da da English E En =20 en en Esperanto — Eo =089.2 eo eo Spanish S Es Sp =60 es es French F Fr =40 fr fr Finnish — Fi =945.41 fi fi Greek G Gr =75 el el Hebrew — He =924 iw he Hindi — Hi =914.3 hi hi Hungarian — Hu =945.11 hu hu Italian I It =50 it it Interlingua — Ia =089.7 ia ia Interlingue — Ie =089.6 ie ie Indonesian — In =992.21 in id Japanese J Ja =956 ja ja Korean — Ko =957 ko ko Latin L La =71 la la Dutch — Nl =393.1 nl nl Norwegian — No =396 no no Polish — Pl =84 pl pl Portuguese — Pt =690 pt pt Russian R Ru =82 ru ru Romanian — Ro =590 ro ro Sanskrit — Sa =912.3 sa sa Serbo-Croat — Sh =861/862 sh — Slovak — Sk =854 sk sk Slovenian — Sn =863 sl sl Swedish — Sv =397 sv sv Turkish — Tr =943.5 tr tr Ukrainian — Uk =83 uk uk Urdu — Ur =914.31 ur ur
After decoupling the country code into ISO 3166 in 1974, the first edition of the standard ISO 639:1988 Code for the representation of names of languages was published with a framework of uniformly two-letter identifiers in lowercase Latin alphabets, mostly identical in format and vocabulary to that of the current ISO 639 Set 1.
Since then, the standard has been adopted as a fundamental technology of the rapidly expanding computer industry (RFC 1766), leading to development of more expressive three-letter framework, published as ISO 639-2:1998, largely based on MARC codes for languages. The original two-letter system was redefined as ISO 639-1 in 2001.
Seeking for more extensive support of languages for widening applications, separate supersets of the ISO 639-2 namespace that cover individual languages and groups were established as ISO 639-3 and ISO 639-5, respectively. There was also an attempt to code more precise language variants using four-letter identifiers as ISO 639-6, which was later withdrawn and to be reorganized under another framework, ISO 21636.
Relatively constant updates in parts of ISO 639 had been handled by each own authority in charge until the publication of ISO 639:2023, which harmonized and reunified the body text of former standards and brought about organizational change with a joint maintenance agency supervising all sets and issuing newsletters. The maintenance agency is located in Norway.
Current sets and historical parts of the standard Set (past Part) Former name (Codes for the representation of names of languages – ...) Language Coding Agency First edition Current No. in list () Set 1 Part 1: Alpha-2 code Infoterm 1967 (original ISO/R 639) 2023 183 Set 2 Part 2: Alpha-3 code Library of Congress 1998 2023 482 + 20 B-only + 4 special + 520 for local use Set 3 Part 3: Alpha-3 code for comprehensive coverage of languages SIL International 2007 2023 7,916 + 4 special + 520 for local use (ISO 639-4) Part 4: Implementation guidelines and general principles for language coding ISO/TC 37/SC 2 2010-07-16 2023 (not a list) Set 5 Part 5: Alpha-3 code for language families and groups Library of Congress 2008-05-15 2023 115 (including 36 remainder + 29 regular groups from ISO 639-2) (ISO 639-6) Part 6: Alpha-4 representation for comprehensive coverage of language variants (withdrawn) Geolang 2009-11-17 withdrawn 21,000+
Each set of the standard is maintained by a language coding agency, which adds codes and changes the status of codes when needed. ISO 639-6 was withdrawn in 2014,ISO 639-6:2009, ISO. and not included in ISO 639:2023.
Characteristics of individual codes Scopes: Individual languages Macrolanguages (Set 3) Collections of languages (Sets 2, 5). Some collections were already in Set 2, and others were added only in Set 5: Remainder groups: 36 collections in both Set 2 and 5 are of this kind — for compatibility with Set 2 when Set 5 was still not published, the remainder groups do not contain any language and collection that was already coded in Set 2 (however new applications compatible with Set 5 may treat these groups inclusively, as long they respect the containment hierarchy published in Set 5 and they use the most specific collection when grouping languages); The only collection which previously assigned with two-alphabet code is Bihari (bh) during the Part 1 era, which deprecated in June 2021. Regular groups: 29 collections in both Sets 2 and 5 are of this kind — for compatibility with Set 2, they can not contain other groups; Families: 50 new collections coded only in Set 5 (including one containing a regular group already coded in Set 2) — for compatibility with Set 2, they may contain other collections except remainder groups. Dialects: they were intended to be covered by former ISO 639-6 (proposed but now withdrawn). Special situations (Sets 2, 3). Reserved for local use (Sets 2, 3). Also used sometimes in applications needing a two-letter code like standard codes in Sets 1 and 2 (where the special code mis is not suitable), or a three-letter code for collections like standard codes in Set 5.
Types (for individual languages): Living languages (Sets 2, 3) (except Sanskrit, all other macrolanguages are living languages) Extinct languages (Sets 2, 3) (599, 5 of them are in Set 2: chb, chg, cop, lui, sam; none are in Set 1) Historical languages (Sets 1, 2, 3) (213, 35 of them are in Set 2; and 5 of them, namely ave, chu, lat, pli and san, also have a code in Set 1: ae, cu, la, pi, sa) 124 of those were categorised as Ancient languages, this type has merged into Historical since about 2024 Constructed languages (Sets 1, 2, 3) (23, 9 of them in Set 2: afh, epo, ido, ile, ina, jbo, tlh, vol, zbl; 5 of them in Set 1: eo, ia, ie, io, vo)
Individual languages and macrolanguages with two distinct three-letter codes in Set 2: Bibliographic (some of them were deprecated, none were defined in Set 3): these are legacy codes (based on language names in English). Terminologic (also defined in Set 3): these are the preferred codes (based on native language names, romanized if needed). All others (including collections of languages and special/reserved codes) only have a single three-letter code for both uses.
Relations between the sets
The different sets of ISO 639 are designed to work together, in such a way that no code means one thing in one set and something else in another. However, not all languages are in all sets, and there is a variety of different ways that specific languages and other elements are treated in the different sets. This depends, for example, whether a language is listed in Sets 1 or 2, whether it has separate B/T codes in Set 2, or is classified as a macrolanguage in Set 3, and so forth.
These various treatments are detailed in the following chart. In each group of rows (one for each scope of Set 3), the last four columns contain codes for a representative language that exemplifies a specific type of relation between the sets of ISO 639, the second column provides an explanation of the relationship, and the first column indicates the number of elements that have that type of relationship. For example, there are four elements that have a code in Set 1, have a B/T code, and are classified as macrolanguages in Set 3. One representative of these four elements is "Persian" fa/per/fas.