Is there any concensus as to what language the Nords originally spoke? I believe that the "common" language of the game (English or German or whatever language you set it to) is supposed to be Cyrodiilic, because Tamriel was once an Empire and Empires (eg Rome) spread their language.
But the Nords used to be efficient if not fluent in Dovahzul, right? Does that mean that WAS their language, or did they have a Nordic language?
Just because they are "Nord" and very heavily influenced in the game design by Scandinavian lifestyles and ideologies (Norse, Icelandic...) doesn't mean they would speak something Germanic (obviously). It's an alternate universe, technically speaking, so Germanic languages don't exist. I find it funny that we automatically go straight to Old Norse or Old English for inspiration for their language (and even the Dov language), when it really has nothing at all to do with it.
So in that sense, in a fan fiction where the local's language is referenced, even Cyrodiilic would be up to one's discretion, though I think many would agree that Latin would be their "influence".
If Nords originally spoke Dovahzul, that'd make it a helluva lot easier than were it based on/similar to Old Norse. From a fic author's perspective, anyway.... :)