In Africa they don't say Excuse Me

This was Joseph's follow up to me telling him at dinner not to interrupt when we are talking. We said he has to say "Excuse Me", and then we will tell him whether or not he can talk. He says in Africa, they say "Boo-Ah" and they raise their hands. And at school they don't say "Excuse Me" either, they raise their hands. He then went on to speak of China and other important international topics.