Wittgenstein speaks of "hinge propositions" in this connection:
That is to say, the questions that we raise and our doubts depend on the fact that some propositions are exempt from doubt, are as it were like hinges on which those turn […] But it isn’t that the situation is like this: We just can’t investigate everything, and for that reason we are forced to rest content with assumption. If I want the door to turn, the hinges must stay put (OC 341–343).
Neither knowable nor doubtable, for Wittgenstein, Moore’s “obvious truisms of the commonsense” are “hinges” (OC 341–343): apparently empirical contingent beliefs which perform a different, basic role in our epistemic practices.
Now consider Chomskian doctrines about language acquisition: we need linguistic schemata as much as, or even more than, we need individual cases (or, we have some schema ready at hand in our minds and we are prompted, by evolved neural wiring, to apply these schema to cases). Or this can be granted regardless of whether one traces this insight to Chomsky specifically. Anyway, the point would be that "the limits of language," as a phrase (in a language!), can have a schematic value, and then we will find not so much a "canonical" list of the same hinges upon which everyone's doors swing, but common types of hinges for the many and varied such doors (as can be peculiar to particular people).
It is difficult, for example, to argue, even with oneself, about the "existence" or non-hallucinatory status of the physical world, since one will tend to voice doubts aloud, either by literally speaking them aloud, or by writing them in public. There is a pragmatic catch in trying to prove, to someone else, that that someone else has no proof that the person they are speaking with (you!) is "real" as opposed to a philosophical zombie. And there is one contributor to this site who has emphasized that denying the existence of language, while using language, seems self-defeating enough such as to prove that language exists (which we might hyperbolically doubt, after all).
But so unfortunately or not, hinge propositions might be construed as "incorrigible," or as close to incorrigible (one might neither substantively agree, nor actively disagree, with a hinge; but one might also be reliably disposed to reason from some possible hinges but not others; whether this disposition is even an internal justifier for the higher-order claim that some or another first-order claim is a hinge, I will not argue here except to point out that we might argue about/on the level of such metaclaims, too; and the ability to imagine extending our reflection to indefinitely higher and higher orders either indicates an order-based limit in one linguistic direction but not in all directions (one limit out of however many, that is, then)).