This is splendid (if accurate--my entire problem with Heidegger is that I can never figure out what he's on about)!

I must say at the level of understanding I have now after your article (which has crystallized a few thoughts from "I can't tell what he means" to "oh, maybe he means that"), I'm rather inclined to agree with Ayer. Plus I now suspect that in the shift to Dasein mattering at all for anything, any sort of practical epistemology gets thrown under the nihilism bus (which always seems to want to drive over everything in philosophy).

(Side note: the whole language thing seems a red herring, given results on the equivalence of computing. Certain structures of language might make it somewhat easier to express certain ideas, and of course if you keep referring to the same idea multiple times you might want to use jargon to abbreviate the concept, but it seems like everything ought to be in reach of every even minimally comprehensive language. Not that you can prove this like you can with computational systems, but I don't think we have any reason to suspect otherwise.)