I suspect this may cause issues when BtRL comes out too so I'd better bookmark the explanation for later use.
How do I change the language settings for FS2 - The retail launcher won't let me?The only way short of a reinstall of the game using a copy from a different language is to edit the registry entry directly. Although relatively simple to do this is not something you should deviate from these steps when doing. Editing anything else in the registry can easily lead to a broken copy of Windows which is only fixable with a reinstall.
1) Go to:
Start -> Run.
2) Type in "Regedit", and click Ok
3) Go to the following folder:
HKEY_LOCAL_MACHINE -> Software -> Volition -> Freespace2
4) Backup your Registry, just to be sure. Do this by clicking:
Registry -> Export Registry File. (File->Export on XP).
(Export "All" if you want, if you're worried you'll screw up something somewhere else by accident. Otherwise just export the selected branch.)
5) Right mouse click on the Language entry. Choose modify
6) A new window will open with a language in it. Change this to English. (The capital E may be important so don't forget it).
7) Click OK and close regedit.
