Non-descriptive (in Austin's terminology: "non-constative") statements have offered also within the Speech Act theory a chance to re-consider epistemological issues.
In this connection, let me focus on the opposition of "false" and "wrong" in this passage from Austin's first lecture:
In the particular case of promising, as with many other performatives, it is appropriate that the person uttering the promise should have a certain intention, viz. here to keep his word: and perhaps of all concomitants this looks the most suitable to be that which `I promise' does describe or record. Do we not actually, when such intention is absent, speak of a `false' promise? Yet so to speak is not to say that the utterance `I promise that…' is false, in the sense that though he states that he does, he doesn't, or that though he describes he misdescribes —misreports. For he does promise: the promise here is not even void, though it is given in bad faith. His utterance is perhaps misleading, probably deceitful and doubtless wrong, but it not a lie or a misstatement, At most we might make out a case for saying that it implies or insinuates a falsehoods or a misstatement (to the effect that he does not intend to do something): but that is a very different matter. Moreover, we do not speak of a false bet or a false christening; and that we do speak of a false promise need commit us no more than the fact that we speak of a false move. `False' is not necessarily used of statements only(Austin 1975 (1st ed.: 1962): 11).
In the second lecture, Austin defines "performative utterances":
These have on the face of them the look –or at least the grammatical make-up– of 'statements'; but nevertheless they are seen, when more closely inspected, to be, quite plainly, not utterances which could be 'true' or 'false'. Yet to be 'true' or 'false' is traditionally the characteristic mark of a statement.
(Austin 1975 (1st ed.: 1962): 12).
In other words, Austin's answer seems to be that illocutionary speech acts show that truth-values cannot be applies to all sorts of utterances, but rather only to the sub-set of constative utterances.
More in general, Austin's point is that illocutionary speech acts are just acts. And, like any other act, they can fail to attain their result or be miscarried. His analysis, hence, plays down the linguistic specificity of Speech Acts.