Well, I doubt that he would speak English because Soviet schools usually taught German. So, I believe that someone has translated it to him. Anyway, maybe there is a way to ask him whether he can speak English and when he learned it.My new headcanon to make this make sense would be he got an English copy and was fluent in English, or had someone translate the whole thing for him.
P.S. I just learned that this guy has like... Six kids.