Language entitles you to moral status

I have finally started reading one of my four books from the library on animals and ethics. I chose "Taking Animals Seriously Mental Life and Moral Status" by David DeGrazia. I admittedly haven't read very far yet, but am already amazed at the assumptions of anti-animal rights defenders. R.G. Frey wrote in his book "Interests and Rights" that animals have no interests because they have no desires. They have no desires because they can't have beliefs. Belief is necessary for desires, because to desire something you have believe that it is missing and this belief must be stated as a sentence! Since animals don't think in sentences they can't have beliefs. Finally, because animals lack interests they have moral status.

So that's the argument. It's bizzare. To start at the beginning I don't believe that desires have to based on beliefs and that either of these need to verbalised in sentences. If I see an ice-cream and I desire it. This is more of a physical/emotional urge/sensation. If I am frustrated because I've been couped up in the house all week, I don't have to have a sentence for the fact that I just wish to break down the doors and run outside. Secondly, there are many, many things that can't or don't have to be verbalised through words. Language is just a tool for communication and expression. Any artist will know that we express ourselves through many means: music, art and dance, for example. My highschool music teacher, Mr De Beer wrote that "Music allows one to express, that which must be expressed but cannot be through words" (I may not have got the quote exactly right.)

Anyone who has has interacted with animals can see that animals have desires, from continuous meowing asking one for more food or eagre anticipation when one touches the leash. It seems that philosophers, so desparate to stick to some particular philsophical-ethical framework, allow themselves to come to ridiculous conclusions that are refuted by evidence. I think they should be more scientific about it. If it doesn't match reality (in any particular instance), then the framework doesn't work and needs to be adjusted or scrapped!