ISO 639
ISO 639 is the standard developed by the International Organisation for Standardisation (ISO) for the identification of languages.
The standard currently consists of six parts, numbered ISO 639-(1-6). Of these, the two-character standards ISO 639-1 and ISO 639-2 have become obsolete; the about 400 codes they distinguished were soon exhausted, while competing three-character systems such as the standard used by SIL in the Ethnologue, and ANSI Z39.53 (also known as the MARC language codes) proved more adequate.
SIL was then asked to participate in the development of ISO 639-3, a 3-letter standard to which the system used in Ethnologue was equated.
ISO expects to publish ISO 639-5 and ISO 639-6, which deal with genealogical classification and language variation, respectively, in 2008.
