I was looking for the german version for the gog version and instead of pulling out my 2 CDs from some of the containers with CDs this thread on steam was absolutely helpful for me: steamcommunity.com/sharedfiles/filedetails/?id=1161336852

Edit: It does not allow me to post full http/https links here, please copy the URL above into a new tab

The GOG version has german language already included. No need to do any manual patching.
You can select the language before downloading (english, german, french, spanish)

Die deutsche Sprachausgabe ist RNG. Meistens aber ohne Funktion.