I would probably agree about "XX" or "IAN". But ISO/TC46 tends to like
uniformity in their schemes and, since they have never contemplated
single-character registrations, and it has taken them more than a decade
to become serious about moving to three characters, we are probably
reasonably safe.
Unless ISO maliciously tries to do so, yes, probably.
Anyway, as 26*26*26+26*26=18252, the 2 or 3 letter space is not large
enough to give meaningful names to all the languages in the world.
Which is why the latest proposal doesn't have such limitations. If ISO-639
version 2539 has 100 letter codes, then Content-Language will be able to
handle it. But at the moment, the 2-letter and future 3-letter codes are
all we have, so that's all that are specified.
Harald, it may be worth saying in your draft that languages codes are of
arbitrary length (up to some suitably large maximum) and will change over
time, so should not be hard-wired into a program, but appear in secondary
configuration files instead. Or some such weasel wording.
I suspect that long before all people of the world have access to e-mail
communications, and want to use their own languages, that we'll all be
speaking some Japano-English dialect anyway, and we'll only need one
language code. :-)
As for time-stamping: I think that is going a little overboard. We are
talking about e-mail communications, with messages that have a fairly short
life-time. Within the life-time of an e-mail message, the names of the
languages and countries are not going to change all that much. Even if
messages are stored in archives (as most of USENET is), then the Date: header
on the messages is sufficient to say "country code xy as it was in 1993"
if that kind of information is important.
There is a need to cope with ancient languages and linguistic notations, but
except for some twisted individuals who delight in "breaking the system",
e-mail, in the form of text/*, is not the best way to do this. Rather some
kind of marked-up document format would be better, especially since it is
likely that explanatory text in a current language would be wrapped around
the ancient writings or linguistic notations. This is beyond the scope of
the IETF.
Cheers,
Rhys.