So, Darcy disappears (except for Lizzy's quizzing of her aunt, ch. 25, which confirms her dislike of Darcy) with hardly a trace when he joins the Bingley sisters in a trip to London to talk Bingley out of such a shameful match as Jane represents.

He's finally heard from again when the company, shortly after their arrival at Hunsford, get word that he is expected to visit Rosings in a couple of weeks (ch. 30).

Once arrived, he remains his usual inarticulate self, replying briefly to direct questions.

Has anyone else noticed that no one is in the least surprised at Darcy's steadfast silence? not Lady Catherine, not Fitzwilliam? --though I suppose it should not be expected that Lady Catherine would notice anything at all beyond her own chatter :-).

His comportment toward Lizzy is beginning to attract Charlotte's notice, at least (chs. 30, 32), but not yet enough to cause her any serious hope for Lizzy. She hopes, but doesn't really believe in Darcy's budding regard.

Even when he arrives at the parsonage and finds Lizzy alone (ch. 30), he can't bring himself to talk. He is drawn by Lizzy into a short exchange regarding Bingley's residence at Netherfield, then, after a (long?) silence, feels constrained to say something, which results in the nearest we have seen so far to a real conversation: the parsonage exchange, which soon migrates to distance from home, which results in his comment that Lizzy could not "have been always at Longbourn."

He withdraws his attention suddenly ("experienced some change of feeling"), and conversation is at an end (except a "short dialogue on the subject of the country") until Charlotte and Maria return, whereupon he leaves.

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So, we have so far dozens of appearances of Darcy, most of which result in two, one, or no sentences in response to someone else's prompting.

We have for the first time two instances in Chapter 10 of Darcy opening his mouth independently (i. e., not in response to another's prompting). We have one of his asking Lizzy to dance, and the attempt to talk about books in chapter 18. There are allusions to "odd unconnected questions" (ch. 33), which we may reasonably attribute to Darcy's unprompted queries.

We have half a dozen cases where he says more than a couple of sentences. Then...

The proposal

Darcy has more speech quoted, and Austen alludes to even more, than we have seen so far. But the word "speech" is key here: this is hardly a conversation. It's a speech, responded to by a counter-speech from Lizzy, responded to by (I'm pretty sure) the longest speech we've yet seen from Darcy ("And this is your opinion of me!"...). (Yes, I'm aware there are a couple of other short lines mixed in).

After her final response, he quits the field again with a (gracious? :-) salutation.