Hey there
Basically you can try to play the EV with German voice, but there will be several times when you will encounter problems.
The main issue is that we have rewritten the dialogue for the EV, so the dialogue in the EV isn't a literal translation - there are many new sentences, sentences where the entire structure or even the flow was changed to fit new sentences in the old dialogue chart (has something to do with Skyrim's limitations on dialogue length).
There are even cases in which the subtitle will say something entirely different than the voice.
This led to our decision that we won't release an EV with German subs, as it would seem really amateurish.
To get an EV with German subs, one would have to take the German version and translate every dialogue sentence from scratch, this time literally and in the correct flow, so that the voices would match - and that would be a new translation project on its own.
Best Regards,
Caleb.