Why doesn't America have other singers that don't speak english?

Ok so take Lady GaGa for example. She is like world famous (duh). Anywho the other day she performed for Japan's MTV award show. She sang in english, but it seem as if the people could still understand her. First of all can they understand her or what is going on there? Second, why doesn't america have famous international pop stars from like china that speaks Chinese that we listen to. Do you get what I mean? Its hard to explain. SO if you could tell me the answer that would be great!! :D