I have (set-language-environment "Latin-1").  And, well, you can see
my own From header.

Apparently, some clients (Gnus included) don't seem to take the hint
that the From header is Latin-1, if

  - the default language environment is something other than Latin-1,
    and
  - the body is ASCII-only (there is no CTE header or it says ASCII
    rather than iso-8859-1).

I'm not sure what's supposed to happen.  Maybe Gnus should take a look
at the headers, and if there is a non-ASCII part in it, the body
should at least be encoded in the same non-ASCII encoding.

I'm not at all sure, however, what's going to happen if the header is
iso-8859-1, say, and the body iso-8859-5.

Does somebody know what should happen?

kai
-- 
Life is hard and then you die.