benderfry: GoG support answered me:
Thank you for the information, we will contact the developers about this; it seems there is a bug in the most recent patch that makes the German subtitles inaccessible, and hopefully they will be able to fix it soon.
In the meantime, you can restore your game to an earlier version by using Galaxy's rollback feature, which will allow you to continue playing with German subtitles. I apologize for the inconvenience.
Regards,