The only thing that seemed to work was a fresh new save from the normal Steam loader, but we definitely don’t want that when we have a lot of progress going, right?
The first time I tried changing the language from Italian to English (not only I enjoy the original voice acting, some of the installed mods are coded in English and I found myself with two different languages playing in the game) I literally freaked out trying to figure out what I did wrong, seeing my perfectly modded game failing on me. The most common issue seems to be related to a total game crash, or the voice audio going completely missing and preventing you from even starting new quests because of that.