Since the IATI Language Code List lists only ISO 639-1, does it already includes other standards in ISO 639 set, such as ISO 639-2, 639-3, 639-5 and 639-6 for Alpha-3 and Alpha-4 codes?
Submitted from: http://iatistandard.org/codelists/language
No, we have only adopted alpha-2 codes. At the time of drafting no-one questioned whether this was a sufficiently broad codelist. Is this a problem for you?
Thanks for the background.
Here are some good past experience that we learned from the computer history: ANSI v.s Unicode code pages, which back then ASCII was designed under the hardware resource constrains and there wasn't much need for processing multiple language in the same document or system; but today more and more software begin to adapt Unicode and almost all new web sites use UTF-8; another good example would be the famous Y2K bug.
Even thought there is no immediate needs for the adaption of this ISO, it would be great to ensure such expandibility for the future, so programmers can reserve some flexibility in their codes to allow expansions when the time comes.