I had a German foreign exchange student who wound up coming back here for college. Between High School and College, he had to take another English class. The Germans weren't happy with his English even though he speaks it beautifully. He has the slang down! They insisted that he call pants, trousers and the movies, pictures. He told them that everyone in America would laugh at him. We did laugh when he told us the story, and we assured him that, yes, we would laugh if he said "I'm going to put on my trousers and go to the pictures".