I don't believe it. I think the modal email message today is intra-
organization and that most of those messages are monolingual. I think
that the modal message when intra-organization ones are eliminated is
still probably intra-country, and that most of those are monolingual,
too.
I have to say that I think this is probably overly provincial or
US-centered. In Europe and in Israel, at least, my experience has been
that people tend to be multilingual and switch rapidly back and forth
between multiple languages in many social and work contexts. I see no
reason to assume that email will be different, if the capability for
mutlingual expression is present.
I don't know much about Israel, but my guess is that they use Hebrew
and English regularly. Such messages would be *bilingual*, and ISO
8859-8 is "sufficient" (10646 is not really needed). In Europe,
certain countries are bi- or more-lingual (e.g. Belgium: French and
Flemish; Switzerland: French, Swiss-German, Italian, and Romansh).
Some of their messages could be bilingual or even trilingual, but I
wonder how many of those messages would *require* 10646, as opposed to
8859-1.
In Japan, we sometimes see bilingual (Japanese and English) messages.
There is some demand for mixing Hangul (Korean) and perhaps some
Chinese into their messages. ISO-2022-JP is felt to be insufficient
in this regard, hence the current work on such things as a
multilingual Emacs (mule), which happens to use ISO 2022 (not
Unicode/10646). This is not surprising since the Japanese already
know how to "do" 2022 and they are used to it. It also allows CJK
disambiguation! :-)
I have sometimes seen the need for English/French bilingual messages.
For example, someone on the 10646 list occasionally distributed
documents that had both the French text and an English translation in
it (i.e. something like multipart).
Andrew Hume has also mentioned that the Plan 9 users started using
accented characters and smileys when 10646 became available.
My travels around the world, though not *that* extensive, generally
indicate that by far most people are monolingual, *some* are "truly"
bilingual, and very few are truly tri- or more-lingual.
We have seen some demand for 10646 in email, but we also know that it
is fairly difficult to raise the "lowest common denominator" in the
email environment. That doesn't mean that we shouldn't *try* to use
10646, though!
Erik