Although I am using Kubuntu for quite a while now I am still a noob when it comes to working with something other than KDE.
However, I tried to set up a Debian 3.1 System with fluxbox as windowmanager. After installing a few apps I realized that there was no option somewhere to set the language of the windowsmanager to my mother tongue (German). I guess that is the reason not only why fluxbox comes in English but also all apps I installed are in English.
Can someone please tell me how I change the language so that all apps including the windowmanager will be in German automatically?
It works with KDE, so I guess it works with fluxbox or Xorg respectively at some point.
Thanks a lot in advance...
(I hope I did not leave out any information. If so, tell me...)

Such assumptions are dangerous. I do not use FluxBox myself [used to, but never needed to have it in another language.] KDE is a desktop environment, FluxBox is a window manager. If you are refering to the fluxbox menu/workspace names, those are easily configurable [or at least the portions of the fluxbox menu that launch applications.], it's like creating a custom menu.

That's not exactly what I was looking for. (Besides: That much I knwe about fb.)
I was rather looking for some global setting that tells programs what language they should work in.

Problem solved:

The apps I was referring to were thunderbird and firefox. Simply installing their locale-packages did the trick.
Could have come up with that myself (...well in the end I did...). Didn't know they had locale-packages...

Ah, sorry, I didn't understand what you mean.