Hi all. Trying to swith the language over to French for my son to be able to play the game, I took a look around the web and found how to do it on some website (can't remember which so I regretfully can't credit them). Thought I should share it here with you as it should work for German, French, Spanish and Italian. This should allow you to change the text, but not the voices or the cut-away scenes' language.
I tried it this evening and it seems to work, at least for the start menu. Didn't have the time tp check in depth what was actually translated.
What you need to do is open the "sf10.pak" file that can be found in the "pak" folder with an hexadecimal editor (HexEdit or similar), look for "ClientLanguage" (in ascii format) and change the value of this variable to the one for your preferred language (0 is German, 1 is English, 2 is French... they're referenced in the code). The hex code should change from 31 to 32 (for French). Save the file once done and you're all set !