The phrase Rather, the language is the material from which works (including dictionaries and grammars) may be created seems to deny the possibility of a work being able to create another work.
Remembering that this is a "work" in the strict copyright sense, could you give an example of a [copyright] work that produces other copyrightable works? (that aren't just derivatives).
My instinct is to say that if a copyright work produces something else then it is technical and falls under the auspices of patent protection instead. If you can copyright technology then you circumvent a primary purpose of the patent system - the freeing of inventions to the public domain.
A language is not a copyright work it's not fixed in a medium, for a start. A description of a language would be copyright protected but you couldn't use such protection to do anything beyond stopping the unlicensed copying of the work itself. The lines of code (or sentences in natural language [or other presentations]) aren't derivative of the work itself but of the ideas that the work presents.
Imagining you could copyright a language, and thus effect the licensing of code in that language, would be to me like imagining that the writer of a cookery book had a legal right over anyone making food using those recipes.
