That's why I started my studies with Alex, 'Pepperberg said. 'Some people actually called me crazy for trying this, 'she said . 'Scientists throught that chimpanzees were better subjects, althrough, of course ,chimps can't speak. ' Chimpanzees and gorillas have been taught to use sign language and symbols to communicate with humans bit this is not the same thing as having an animal look up at you, open his mouth, and speak