The comments here are about the "smooth" versus "standard" dances. For the fast dances, there are definite differences between American Rhythm and International Latin. Latin rumba starts on the two beat, American on the one beat. I may not describe this right: there is minimal hip action in Latin, while American emphasizes hip action through bent leg movement. Multiple dance championships in Latin include rumba, chacha, samba, paso doble and jive, while American is chacha, rumba, east coast swing, bolero and mambo.