Hallo!

> \enableregime, \mainlanguage, \setupencoding are English
> commands; texexec is smart enough to detect this, and therefore
> uses the English interface; 

Obviously this autodetectroutine is checking only the präambel.

>  if you want to use the German one,
> use the German corresponding command: \hauptsprache instead of
> \mainlanguage. Or, as the first line of the file put:

That means, that the aktual setting in 'texexec.ini' is of no practical
use, isn't it?

> % interface=de

And than texexec forgets its smartness?

The whole thing costs me a lot of time. I installed context with
'UserInterface de' without a real idea
what it means. I didn't know if it brings me german messages or an german
interface. Then I forgot
this setting and used english statements. All worked well, until I wrote a
little testfile, without präambel,
and tex complains about \chapter{}. It was very strange!

May be, a warning message would be helpfull, say 'UserInterface doesn't
match initial setting!'

Wolfgang