Actually I’m just being silly, but I noticed this morning that Tybalt’s first two lines, literally, are “What?” Enter Tybalt TYBALT What, are thou drawn among these heartless hinds? Turn thee, Benvolio, look upon they death. BENVOLIO I do but keep the peace: put up they sword, Or manage it to part these men with me. TYBALT What, drawn, and talk of peace! I hate the word, As I hate hell, all Montagues, and thee: Have at thee, coward! Reminds me of a neighborhood bully when we were growing up. Whenever you said something that he felt like taking as insulting he’d always start with a “What?” Far from being intimidating, it only made him seem stupid, like he was never fully able to process that he’d been insulted. There used to be a pro-wrestler who did a whole big gimmick out of punctuating his interviews with “What?” whenever somebody else was talking. I realize of course that it is not being used in that context. It’s actually a pretty common interjection in Shakespeare’s dialogue, I count 14 times in R&J alone. Taming of the Shrew has 22!
“What” at the beginning of a sentence does seem to have an air of cluelessness about it. Two other English writers come to mind, each of them more widely read in India than Shakespeare, but for the most part unknown in the US: P.G. Wodehouse, the humorist and Enid Blyton the prolific writer of childrens’s books. Apart from the ubiquitous “What ho?”, Wodehouse’s Bertie Wooster’s uncle by marriage, Lord Worplesdon goes around spluttering”What? What? What? What?” when he’s ticked off about something. Enid Blyton’s Secret Seven series has the dimwitted constable whose favorite interjection is “Ere, what’s all this then?”.
Ram
I always read “What” in that context as more of almost sarcastic remark. At least for Tybalt. It’s used really commonly as you noted, throughout the plays, & it’s rarely a “what?” as in “pardon? / repeat what you said?” the way we say it today.