> From: suzmccarth [mailto:suzmccarth@...]

> What is the difference between the 2 letter code and the 3 letter
> identifier?

Without getting into terminological issues between "code" and
"identifier", or the obvious answer, "one letter"...

ISO 639-1 defines a set of 2-letter identifiers. This standard has its
origins in the field of terminology, and criteria for adding a language
to this set include that there must be developed terminologies for a
language.

ISO 639-2 defines a set of 3-letter identifiers. This standard was
jointly developed by terminologists and librarians, with the latter
mostly responsible for the initial set. The criterion for inclusion in
this set is that there must be at least 50 documents across 5 or fewer
institutions that are in the given language.

ISO DIS 639-3 defines a set of 3-letter identifiers compatible with ISO
639-2 but with the aim of providing comprehensive coverage of languages,
whether living or extinct, naturally-occuring or invented, spoken,
written or signed.



Peter Constable