ISO 639

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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 It was also the name of the original standard, approved in 1967 and withdrawn in 2002^{[citation needed]}.

ISO 639 consists of different parts, of which four parts have been approved (parts 1, 2, 3 and 5). The other parts are works in progress.^[1]

1 The six parts of the standard
2 Characteristics of individual codes
3 Relations between the parts
4 Use of ISO 639 codes
5 Code space
6 See also
7 Notes & references
8 External links

The six parts of the standard

Standard	Name (Codes for the representation of names of languages -- ...)	First Edition	Current	No. In List
ISO 639-1	Part 1: Alpha-2 code	1967 (as ISO 639)	2002	184
ISO 639-2	Part 2: Alpha-3 code	1998	1998	>450
ISO 639-3	Part 3: Alpha-3 code for comprehensive coverage of languages	2007	2007	7704 + local range
ISO/DIS 639-4	Part 4: Implementation guidelines and general principles for language coding	(As of July 2009^[update] in DIS stage)	-	-
ISO 639-5	Part 5: Alpha-3 code for language families and groups	2008-05-15	2008-05-15	114
ISO/FDIS 639-6	Part 6: Alpha-4 representation for comprehensive coverage of language variation	(As of July 2009^[update] in FDIS stage)	-	?

Each part of the standard is maintained by a maintenance agency, which adds codes and changes the status of codes when needed.

Characteristics of individual codes

Scopes:

Individual languages
Macrolanguages (part 3)
Collections of languages (part 1, 2, 5) (part 1 contains only 1 collection: bh; most collections are in part 2, and a few were added in part 5)
- Group
- Rest group
Dialects
Reserved for local use (part 2, 3)
Special situations (part 2, 3)

Types (for individual languages):

Living languages (part 2, 3) (all macrolanguages are living languages^[2])
Extinct languages (part 2, 3) (437^[3], four in part 2 chb, chg, cop, sam; none in part 1)
Ancient languages (part 1, 2, 3) (112^[4], 19 are in part 2; and 5 of them, namely ave, chu, lat, pli and san, also have a code in part 1: ae, cu, la, pi, sa)
Historic languages (part 2, 3) (63^[5], 16 of them are in part 2, none has part 1 code)
Constructed languages (part 2, 3) (19^[6], 9 in part 2: epo, ina, ile, ido, vol, afh, jbo, tlh, zbl; five in part 1: eo, ia, ie, io, vo)

Bibliographic and terminology codes

Bibliographic (part 2)
Terminology (part 2)

Relations between the parts

The introduction to this section provides insufficient context for those unfamiliar with the subject. Please help improve the article with a good introductory style. (October 2009)

The first four columns contain codes for a representative of a specific type of relation between the parts of ISO 639. E.g. there are four elements that have a code in part 1, have a B/T (bis/ter i.e. second and third) code, and are macrolanguages per part 3. One representative of these four elements is "Persian" [fas].

ISO 639-1	ISO 639-2	ISO 639-3	ISO 639-5	#	Description of example
en	eng	eng	(-)	132	185 in Part 1, subtract all special cases for Part 1 codes, 185-2-25-17-4-2-1-1-1=132
nb	nob	nob	(-)	2	individual language, belongs to macrolanguage (nor), same code in Part 2 and has a code in Part 1. The two codes are: nob, non
ar	ara	ara (M)	(-)	25	Part 3 macro, 55 macro total, subtract special cases, 55-24-4-1-1=25
de	ger/deu (B/T)	deu	(-)	15	22 elements where B and T differ. Subtract special cases, 22-1-4-2=15.
cs	cze/ces (B/T)	ces	(-)	1	Element with differing B/T code and the letters from the Part 1 code are not the first two letters of the T code.
fa	per/fas (B/T)	fas (M)	(-)	4	Part 3 macro; the four T codes are: fas, msa, sqi, zho
hr	scr/hrv (B/T)	hrv	(-)	2	Part 2 B deprecated, the two T codes are: hrv, srp. Deprecated 2008-06-28.
no ("M")	nor ("M")	nor (M)	(-)	1	Part 3 macro and containing languages have codes in Part 1, nor: non, nob; no: nn, nb
bh	bih	(-)	?	1	Bihari (bih) is marked as collective despite having an ISO 639-1 code which should only be for individual languages. The reason is that some individual Bihari languages received an ISO 639-2 code, which makes Bihari a language family for the purposes of ISO 639-2, but a single language for the purposes of ISO 639-1. The single are: bho, mai, mag
sh	(-)	hbs (M)	(-)	1	Part 3 macro, ISO 639-1 code deprecated, no part 2 code
(bh)	bho	bho	(-)	3	individual language code in Part 2 + 3, belongs not to a macrolanguage, in Part 1 covered by a code which has equivalent in Part 2 which is a collective. The three codes are: bho, mai, mag
(bh)	(bih)	sck	(-)		individual language no code in Part 2, belongs not to a macrolanguage, in Part 1 covered by a code which has equivalent in Part 2 which is a collective.
(-)	car	car	car		individual language in Part 2 and Part 3, but also included in Part 5 as a family^[7]^[8]
(-)	ast	ast	(-)		individual language in Part 2 and Part 3, no code in Part 1
(-)	bal	bal (M)	(-)	24	individual language in Part 2 and macro in Part 3, no code in Part 1
(-)	mis	mis	?	1	special code: missing code
(-)	mul	mul	?	1	special code: multilingual content
(-)	und	und	?	1	special code: undetermined
(-)	zxx	zxx	?	1	special code: added 2006-01-11 to declare the absence of linguistic information
(-)	qaa	qaa	?	520	reserved for local use, range is qaa ... qtz
(-)	aus	(-)	aus		regular group in Part 2
(-)	afa	(-)	afa		In Part 2 a rest group, i.e. same code but different languages included. In Part 2 "afa" refers to an Afro-Asiatic language that does not have an individual-language identifier in Part 2, and that does not fall into the rest groups "ber - Berber (Other)", "cus - Cushitic (Other)", or "sem - Semitic (Other)", all of which are Afro-Asiatic language groups.
(ar)	(ara "M")	arb	(-)		individual language, belongs to macrolanguage (ara), in Part 2 covered by the macrolanguage code, in Part 1 also covered
(-)	(nic "R")	aaa	(-)		in Part 2 best covered by a rest group, "Niger-Kodofanian (Other)"
(-)	(-)	(-)	sqj		group not coded in Part 2

codes in Part 1 have one or two codes (B/T codes) in Part 2, every language that has two codes in Part 2 has one code in Part 1
- one code: en -> eng
- two codes (#~23): de <-> ger/deu
Part 2 has reserved codes and three special codes
- qaa ... q??, mul, und, zxx
individual languages in Part 2 have a code in Part 3 and have one or no code in Part 1
- one code: eng -> eng -> en
- no code: ast -> ast -> (empty)
collective codes in Part 2 have a code in Part 5
- cover different languages: afa != afa
- cover same languages: aus = aus
one collective code in Part 2 has a code in Part 1
- bih -> bh
some codes in Part 5 have no code in Part 2
- sqj
some codes (#~56) in Part 3 are macrolanguages, they may have
- no Part 2 code but a Part 1 codes and their containing languages have codes in Part 2 and Part 1 (#1): hbs <-> sh (deprecated) ; bos, hrv/scr, srp/scc -> bs, hr, sr
- a Part 2 code and a Part 1 code(#1), while their containing languages also have codes in Part 1 and Part 2: nor -> nor -> no ; non, nob -> non, nob -> nn, nb
- no Part 1 code (#several):
- two Part 2 codes (B/T) (#4): fas, msa, sqi, zho -> per/fas, may/msa, alb/sqi, chi/zho

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.

Delimiting languages

A multilingual page is contained by the CSS class "multilingual", with text in every language contained within the class "lang-xx", where xx is a lowercase ISO 639 two-letter or three-letterlanguage code and the lang attribute. The lang attribute is contextually more correct, but the CSS required to hook into it is not supported by all browsers. If there is no two-letter code, the lowercase three-letter code is used. If you're translating existing messages and don't know what the language is, use the code "und".

Code space

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 26² = 676), ISO 639-2 was developed using Alpha-3 codes (though the latter was formally published first).^{[citation needed]}

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 26³ = 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^[9]. 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 the 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. The upper limit for the number of languages and dialects that can be represented is 26⁴ = 456,976.