I come from a large German family.
If he follows the stereotypes:
1. Expect him to have a rather dry or unusual sense of humor.
2. Don't expect huge, loud displays of emotion (in my experience, German culture does not encourage large emotional displays. That isn't to say that German's are Vulcans or anything. Just don't expect anything too loud or showy in terms of his making his feelings known).
If he says "I don't like (insert thing here)," this could be his subdued way of saying "I hate (insert thing here) with a passion and would rather gouge out my eyes than even think about it.
In terms of dating, make sure that you're being an active listener.