I hate to point out that I find some aspects of Robert Brandom's philosophy to be morally rebarbative for two reasons. First, I don't think it follows from this that he's a bad person. I've never met him, but have had the pleasure to meet many of his students and I have every reason to think that he is a good soul. Second, I think that Brandom is one of the three most important living philosophers, and that the dialectic does in fact go through him. Unfortunately though, our age of media gotchaism has infected philosophy. Just as it's appropriate to judge a celebrity by their worst public moment, it's somehow appropriate to judge philosophers by the worst aspects of their systems. Heidegger's Nazism has absolutely nothing to do with the interpretations of Heidegger by the overwhelming number of American Heideggerians. But tying the Nazism to some part of his system (with more and less plausibility)* suffices in our debased celebrity culture. It's very convenient because it gives us an excuse not to read Heidegger.** Moreover, even if, unlike Heidegger, Brandom's rebarbative views about those who don't speak really is implicated deeply in his philosophical achievements, this wouldn't be a reason not to read him, any more than Cartesian vivisectionists mean we should stop reading Descartes.
Now here is a biographical prelimary. One of my daughter's best friends has apraxia of speech. Every weekend Audrey's friend with apraxia and her sister either come over to our house, or she goes over to their house. It's only recently that Audrey's friend with apraxia has started talking with her sister and Audrey when they are playing together. For a couple of years she didn't speak, and some people with apraxia of speech never talk. In addition, I know two people who suffered severe aphasia after a stroke. Both recovered their ability to speak. But for many people, aphasia is a permanent state. Finally, people born deaf in communities with no sign language often end up being permanently non-linguistic. There is a largish literature on people in this situation who are taught a first language at later ages, examining how their difficulties tie with the lessened ability to learn a second language as you get older. But many such people never learn a language.
I hope that anyone reading this will agree that any view that denies moral worth to those with severe apraxia, aphasia, and deafness is in fact a wicked view. And, to the extent that one can separate moral and epistemological concerns, anyone who actually knows or has studied people with apraxia, aphasia, and deafness who do not have language will not deny sentience to these people. Yet Robert Brandom does both.