We've already seen from the screenshots that Crusader Kings II's interface will use English text, so language is represented in the game. Hope this helps. 
There will probably be culture groups since they've been in EU III and Vicky 2. Which means there'll be a Scandinavian culture group consisting of at least Swedish, Danish and Norwegian (even though 1066 Jutish and Geatish were still well existing cultures). Likewise there'd be Germanic, Celtic, French, Iberian culture groups consisting of sub- cultures.
However, as said, every little county had it's own lingua during this Time Period.
We've already seen from the screenshots that Crusader Kings II's interface will use English text, so language is represented in the game. Hope this helps.![]()
It would be interesting, from an alternate history perspective if, for example, there was the Scandinavian cultural group, but that the division between Swedish, Danish, and Norwegian was created over time due to the borders of the kingdoms. Though I guess that could be well represented in an EUIII-like cultural assimilation event for provinces. But it would be good if culture spread in a more organic way, similar to tech spread in CK.
Or even worse... The game suddenly shifts and everything changes to be written in Medieval South Germanic...![]()
Culture spread and tech spread in CK1 were pretty similar, culture would spread from one province to the next in much the same way as tech did. However the realm ruler's culture needed to match the spreading culture, that was one of the big things favoring (or disfavouring) cultural spread in the game.
On topic: I think this could be very hard to model. It is generally recognised (I think) that this was the time of language continua, i.e. on a line extending from the Swiss Alps through the Rhineland to Northern Germany and the Netherlands to England, the inhabitants of adjacent territories could all communicate, but those with greater distances between them could not. I have no idea how this could be modelled sufficiently simple for a game while staying close to historical facts, except by staying with the much simpler "culture" mechanic.
It would surely be interesting if done correctly. I for one would like to see it as a core part of the game.Yeah I even bet this will be the case if I know paradox correctly as this one of the favourite what if? scenario for scandinavians, the others are of course permanent nordic settlements in america and the swedish Rus managing to hold on to their russian empire.
This game will be so awesome !![]()