The fallacy I often hear uttered is that if we can stuff Unicode into
the MIME header as the charset, then we can avoid the problem of having
to define a CHARSET tag (since Unicode encompasses most national char-
acters). But this way of thinking is WRONG. Unicode doesn't provide
a mechanism for varying sort order and other things that vary accord-
ing to locale and language. To do this, THE UNICODE STANDARD ITSELF
SAYS THAT ADDITIONAL TAGS ARE NECESSARY for this sort of thing.
The Unicode standard says such information is necessary if one wishes
to perform in a plain-text encoding environment the following:
(1) culturally correct sorting and
(2) high-quality typographic formatting
Show me where in HTML or in HTML applications that either of these
requirements exist and I will agree with you that a language tag is
needed; however, I think that you are going to have a difficult time
showing where these are actually required, in which case your argument
(and others of the same ilk) is simply a red herring.