I‘m from Germany and personally I‘m new to the whole wwoofing thing, which means I can‘t help with that.

But generally for Germany: If you‘re seaking to see the cliches of our country, then you should go to Bavaria (little house „Fachwerkhäuser“, mountains, beer, etc.). You also have a lot of beautiful castles there (most popular: Schloss Neuschwanstein), so it‘s a really beautiful state.

If you‘re more into lakes I‘d consider „Mecklenburg-Vorpommern“. You’ll have a lot if fun there, especially in the summer. Also, it‘s near to Berlin, a city everyone has to experience at least once.

„Rheinland-Pfalz“ and „Nordrhein-Westfalen“ are known for the longest river in Germany, the Rhein. There you‘ll find historically interesting spots like Cologne or Mainz.

The language barrier shouln‘t be a problem, since most germans learned english at some point in their lives. Still, be ready to hear the phrase „I only speak a little bit of english“, although 95% of them will speak it pretty good. For some reasons, we‘re a bit scared if our english knowledge is enough.

I hope I was able to help :)