" We have historically focused on the use of human language, for example, as a unique characteristic that separates us from animals and makes us "better." Who says? In the first place, there is, and we have seen, compelling evidence that animals other than humans can learn human language. Moreover, there is a great deal of empirical evidence that animals are able to communicate, often in very sophisticated ways, with members of their own species. The more relevant question, however, is what is inherently better about a species that uses human words and symbols to communicate? Birds can fly; we cannot. What makes the ability to use words and symbols better for moral purposes than the ability to fly? The answer, of course, is that we say so. "

― Gary L. Francione , Introduction to Animal Rights: Your Child or the Dog?