If you wanted to call and speak in person, I would be surprised if they didn't speak fluent English. In fact, I think the school children have better grammer skills then I do. I spent multiple weeks in Munich and Berlin and never once had to use my terrible German to talk with people at large. While I didn't spend a lot of time in Frankfurt, I would expect to the locals to be fluent in English there as well.
Unlike the USA, major portions of Europe are fluent in more then one language. The business community itself has an even higher percentage of multi-language people in it.
FWIW, I have sent email all over the world to companies that have products I was interested in at some point in time. Many of these companies did not have a prescense in the USA marketplace. Sometimes it took a while to get a response and I ended up writing to a son or daughter of an employee, or a young college intern or new hire. In the end, I always got a message written in English that I understood and answered my questions in response to my inquiry.
