Communicating without words

In the book Animals and Why They Matter, Midgley gives a quote from R.C. Frey, “Animals cannot have rights because they cannot have interests. They cannot have interests because they cannot have desires or emotions. They cannot have desires or emotions because they cannot have the thoughts required for them. And they cannot have those thoughts because they cannot speak. From my point of view, I disagree with Frey and believe it does not make sense. Frey is only basing rights and interests on speech. He makes it feel like the only way to have rights and interests is to communicate with words. In contrast, a human or even animals do not have to always use words to communicate. They can use gestures or emotions to communicate as well. For example, babies do not use speech to communicate their interest or emotion. Does that mean they have no rights? Society considers babies to have rights, so what is the difference between a baby that cannot talk and an animal that cannot talk? It is clear that animals have interests and emotions. A dog shows emotion of excitement by wagging its tail. Also, a dog shows interest in wanting to go on a walk by holding his leash and standing by the door. Doesn’t this give prove that animals, dogs, have interests even though they do not use words to communicate?