One of my colleagues here at Leiden is reading P.G. Wodehouse. She told me about this because she had noticed what seeemed to her a peculiar construction, as in “It does make it awkward, what?” and “Better take a look round, what?”. Is this oldfashioned British English, or dialect, she asked me. For me it is ages since I read any Wodehouse novels, not since my teenage years anyway, so I wouldn’t know, except that the construction suggests upper-class usage to me. But I promised to consult the readers of this blog. Does anyone have an idea?
Checking his wikipedia entry just now, I was struck by how similar Wodehouse’s life and career was to Raymond Chandler’s, whose biography I’m reading at the momen. There is not much of an age difference between them, they went to the same school (Dulwich College), both lived in England and the US during periods of their lives, both became writers after unsatisfactory early careers, and both worked for Hollywood.
So I really must reread some of Wodehouse’s novels, as well as the biography I have of him, but have never read.
Bridging the Unbridgeable 
The Concise Oxford English Dictionary (2008) has “what” as an interrogative adverb meaning (1) to what extent and (2) informal, dated, used for emphasis or to invite agreement: “poor show, what?”
I remember a rapid “What what?” being uttered at the end of a statement in dialogue satirizing the speech of upper-class Brits, a long time ago.
Yes, it’s definitely extremely dated upper-class British, evoking the 1920s and ’30s, or maybe even earlier. There was a character in John Masefield’s ‘The Box of Delights’ (published in 1935) who said “What, what!” after everything he said. After I read it to my children, it became a family phrase for a number of years. It doesn’t really mean much, but is used for emphasis and out of habit. “Jolly good show, old boy, what what!”
An expression even more intriguing in his works is ‘…,eh, what?’ Makes the whole thing sound more conversational, eh, what?!
In the Wodehouse canon, “what?” is mostly – but not always – used in the same way as the invariant tag question “eh?”. It generally performs the phatic function of keeping contact between speaker and hearer but has various subfunctions such as expressing the speaker’s weak doubt or asking for the hearer’s opinion.
In another book, for example, it is used when one of his characters unexpectedly bumps into an acquaintance: “Well, well, well, what?” In this instance, it has a dual function –softening the slightly confrontational “well, well, well” whilst trying to engage the hearer into conversation.
I wonder if this could also be an upper-class version – a precursor, if you like – of uptalk. The “What?” always has rising intonation and Wodehouse is fond of adding it to statements so that the statement ends in rising intonation as though it were a question, which is the modern trend among teenagers’ conversations (e.g. innit?, yeah?).