I don't plan to buy the game but it should be possible.
But I got to verify some things I found out.
I can find out where
BGEE is installed by going through the registrys uninstall-entries that exits.
When I find one with the DisplayName "Baldur's Gate - Enhanced Edition", it's a hit.
If Publisher "Beamdog" is set, it's a beamdog-install, otherwise Steam.
Beamdog puts the game underneath Data\0766, Steam does not do that.
If the installation was copied (if that is possible with
BGEE), I'd offer selecting the folder and check if baldur.exe and chitin,key is in there and a subfolder lang\de_DE or en_US.
Other installations don't have those folders.
Starting the game, documents\Baldur's Gate - Enhanced Edition\baldur.ini is created. If there is e.g. a line
'Language', 'Text', 'de_DE', you'd have changed the text from English to German, otherwise not and en_US would be used.
I can extract the mods into the folder where the chitin,key is, create an override-folder and start the mods by using something like the mod Valerie did:
weidu valerie\valerie.tp2 --script-style BG2 --tlkin .\lang\en_US\dialog.tlk --tlkout .\lang\en_US\dialog.tlk --log valerie_bgee.DEBUG
Or I could copy and paste the dialog-files and put them back afterwards. I'd prefer that since I don't want to fiddle with mlink - my OS does not support that and I couldn't test it.
I could blindly throw in the mods from
here, use the "common" megamod idea for sorting and that would be it - or better, another guy does that since I was never interested in fiddling with that at all.