People mostly speak German and English in Berlin. Mark Twain once said, "I don't believe there is anything in the whole earth that you can't learn in Berlin except the German language" and I think that's true. It's so easy to get by only speaking English that I need to be deliberate about keeping up with my German.
The currency in Germany is the euro, and using coins, especially one euro and two euro coins, is very common. I try to pay in coins when I can, but I recently spent a day buying things only in 20 cent coins because I'd collected too many.
Usually a bottle of water costs about one euro, which is a little over $1.
It was one of my roommates' birthdays this week, so my other roommate and I took him out for lunch. We went to his favorite Indian restaurant. He's from India, and he had the best recommendations about what to order.
Berlin is considered the capital of techno music, and I got to hear some when I went out dancing this weekend. I really liked one of the DJs who played a few songs accompanied by a keyboardist and two trombone players!