In the normal version the error does not occur, but with your savegame we cannot solve the problem.
That you started the game with an unfinished / incorrect translation (and then switch between) is very very bad.
Such a thing shoots up a lot of things and nobody knows the long-term consequences for your savegame.
so these are your options:
-install Enderal new
(to remove all the remains of the mod, you should delete the folder:
...\Steam\Steam\SteamApps\common\Enderal
Then repair Enderal
with steam.)
You can select the English or French version in Steam.
(French is currently available through Steam from the French team, but this will not help for your current play)
START A NEW GAME
or
-try to load an earlier save (BEFORE Silberhain, e.g. from the possessed before).
for this you will need to REINSTALL Enderal AND use your old translation mod.
Even if the bug should be fixed, there may be other problems and then we won't be able to help you,
and there is no guarantee for success.
this option does not work.
I'm sorry there's no better answer.