"gd" and "ga", or "gla" and "gld"

[John Cowan]

Caoimhin O Donnaile scripsit:

> I seem to remember a rule saying that two-letter codes should be used
> if these are available, but my tidy mind would prefer three-letter codes
> for all languages, and I have a feeling that these might be on the
> way with the unification between Ethnologue codes and ISO 639-2.

The rule is indeed to use 2-letter codes where they exist.  This is
needed not so much for concision as for backward compatibility with
the millions of pages labeled "en", "de", "es", "fr", and so on.
The reason that 3-letter codes are not permitted in such cases is
to make the way of those who would interpret those codes easy:
if authors were permitted to use either "en" or "eng", readers would
have to specify both "en" and "eng" in all cases, since those values
are synonymous.

-- 
John Cowan  jcowan at reutershealth.com  www.ccil.org/~cowan  www.reutershealth.com
"If I have not seen as far as others, it is because giants were standing
on my shoulders."
        --Hal Abelson