Instead, the fundamental idea is that language is used above all to communicate (i.e. rather than to denote or represent, which it does in only a derivative manner). Similar ideas are already present in Davidson (q.v. "Reality Without Reference," and "Communication and Convention," in Inquiries), but here he spells out the implications more provocatively. Indeed, in asserting a primary role for the intentions of the speaker in determining meaning, he provokes suspicions of "internalism" and downright semantic nihilism.
The specific thesis he rejects is that "[t]he systematic knowledge or competence of the speaker or interpreter is learned in advance of occasions of interpretation and is conventional in character." Okay, that's pretty much what I said above. But later on, he elaborates: "[i]n principle communication does not demand that any two people speak the same language. What must be shared is the interpreter's and the speaker's understanding of the speaker's words."  Now there are some constraints on this sharing, some of which involve what can count as a possible communicative intention of the speaker in the given situation (here leaning on Grice's analysis of same); and it is these constraints which separate Davidson's account from nihilism and/or internalism.
Here Davidson points to Keith Donellan's previous (albeit somewhat differently focused – Davidson explains but I will skip that part) discussion of similar matters. Alfred MacKay had accused Donellan of Humpty Dumptyism ("When *I* use a word, it means just what I choose it to mean"), and in reply, Donellan "explains that intentions are connected with explanations and that you cannot intend to accomplish something by a certain means unless you believe or expect that the means will, or at least could, lead to the desired outcome. A speaker cannot, therefore, intend to mean something by what he says unless he believes his audience will interpret his words as he intends (the Gricean circle)." As quoted by Davidson, Donellan says:
If I were to end this reply to MacKay with the sentence 'There's glory for you' I would be guilty of arrogance and, no doubt, of overestimating the strength of what I have said, but given the background I do not think I could be accused of saying something unintelligible. I would be understood, and would I not have meant by 'glory' 'a nice knockdown argument'?Davidson approves of this reply (and then explains a disagreement I have here elided). Okay, let me just quote the money paragraphs and then I'll stop.
Humpty Dumpty is out of it. He cannot mean what he says because he knows that 'There's glory for you' cannot be interpreted by Alice as meaning 'There's a nice knockdown argument for you.' We know he knows this because Alice says 'I don't know what you mean by "glory"', and Humpty Dumpty retorts, 'Of course you don't – til I tell you.' It is Mrs Malaprop and Donellan who interest me; Mrs Malaprop because she gets away with it without even trying or knowing, and Donellan because he gets away with it on purpose.One more thing. I think that what this means is that when Wittgenstein asks us to consider whether I can say "bububu" and mean "if it does not rain I will go for a walk," the answer is yes, I can; but only after what he elsewhere calls "stagesetting." Before that, not so much (and certainly not by a Humpty Dumpty-like act of, say, inner ostention).
Here is what I mean by 'getting away with it': the interpreter comes to the occasion of utterance armed with a theory that tells him (or so he believes) what an arbitrary utterance of the speaker means. The speaker then says something with the intention that it will be interpreted in a certain way, and the expectation that it will be so interpreted. In fact this way is not provided for by the interpreter's theory. But the speaker is nevertheless understood; the interpreter adjusts his theory so that it yields the speaker's intended interpretation. The speaker has 'gotten away with it.' The speaker may or may not (Donellan, Mrs Malaprop) know that he has got away with anything; the interpreter may or may not know that the speaker intended to get away with anything. What is common to the cases is that the speaker expects to be, and is, interpreted as the speaker intended although the interpreter did not have a correct theory in advance.