Answer

I don’t remember the argument, but as you presented it, it seems to me null and void, like the dust of the earth.
I’m willing to accept Premise A, so long as we include in “language” also what we experience with the “eyes of the intellect,” such as abstract mathematical entities or concepts like democracy or kindness.

Premise B is nonsense. The naturalistic fallacy says that there is no connection between ordinary facts and norms. You cannot derive a norm from a fact. But if there are ethical facts, there is no problem deriving norms from them. I observe with the “eyes of the intellect” the idea of morality and “see” that a certain act is moral or immoral. From that it follows that it is forbidden to do it. That is the meaning of an ethical fact. I defined this in my book Truth and Unstable, and also in the fourth booklet on my website.
If one accepts the validity of morality, meaning one does not see it as a mere convention, then one must conclude that there are moral facts (for otherwise—what gives feelings or conventions any validity? That itself is the naturalistic fallacy).
And from this it follows that there is valid morality, and it can also be spoken about in language. Incidentally, the fact is that we do this (see Moore and his waving of the hands, the father of the naturalistic fallacy).   
 
By the way, I don’t see a difference between thinking/experiencing something and speaking about something. Our thinking/experience too can be limited by what it encounters. Everything else may be found in the mind, but only as a hallucination (and not as thought or experience). If so, what you say about language you could say just as well about thought. So if morality cannot be spoken about, then it also cannot be thought about. And really, the conclusion is that there is no such thing.
And from here: if there is such a thing, then it can be spoken and/or thought about. QED.