Quote from Denise in the episode Spoiler: Bert Gets Married
Stuart: Hey, is it weird that a primitive tribe with no contact with the outside world, no technology, speaks English? Denise: Maybe we're speaking their language. Stuart: Well, if that's the case, how can I say the word "helicopter"? They obviously don't have helicopters. Denise: We say "unicorn," but we don't have unicorns. Stuart: I don't want to talk about this anymore.