Elaborate, Gossipy, Confiding, Perceptive, Dense, Hilarious, Quippy
Although Thackeray is not the kind of writer who cultivates a totally idiosyncratic style, it's still relatively easy to recognize his writing because of how funny it is, and how willing he was to mix every kind of humor together. Check out the introduction of the Crawleys. It's got topical humor, political humor, jokes about silly names, and deeply sad irony about the decline of the aristocracy – and all these things work together to give us a sense of this ruined, immoral, thoroughly unpleasant family.
It is related, with regard to the borough of Queen's Crawley, that Queen Elizabeth in one of her progresses, stopping at Crawley to breakfast, was so delighted with some remarkably fine Hampshire beer which was then presented to her by the Crawley of the day (a handsome gentleman with a trim beard and a good leg), that she forthwith erected Crawley into a borough to send two members to Parliament [...]
So first of all, topical humor. In Thackeray's time there was a lot of concern about "rotten boroughs" – counties that got to elect members to Parliament without having many actual residents to represent. In other words, imagine Bill Gates's mansion being declared a state and his getting to send senators and congressmen to Washington to represent him. Queen's Crawley is this kind of place. So how did Queen's Crawley become a Parliamentary borough, anyway? Well, Queen Elizabeth liked their beer and thought her host was hot.
Sir Pitt Crawley (named after the great Commoner) was the son of Walpole Crawley, first Baronet, of the Tape and Sealing-Wax Office in the reign of George II., when he was impeached for peculation, as were a great number of other honest gentlemen of those days; and Walpole Crawley was, as need scarcely be said, son of John Churchill Crawley, named after the celebrated military commander of the reign of Queen Anne. [...]
Sir Pitt was first married to Grizzel, sixth daughter of Mungo Binkie, Lord Binkie, and cousin, in consequence, of Mr. Dundas. [...]
Second, political humor. Every generation of Crawleys has a first name that reflects whoever is the political power of the day, no matter which party or which kind of government they represent. In other words, they switch allegiances just to support the winning team.
Third, funny names. Mungo Binkie? Need we say more?
Miss Rebecca Sharp was now engaged as governess. It will be seen that the young lady was come into a family of very genteel connexions, and was about to move in a much more distinguished circle than that humble one which she had just quitted in Russell Square.
She had received her orders to join her pupils, in a note which was written upon an old envelope, and which contained the following words:
Sir Pitt Crawley begs Miss Sharp and baggidge may be hear on Tuesday, as I leaf for Queen's Crawley to-morrow morning ERLY. (7.1-7)
Finally, there is a sustained joke about the way aristocrats no longer maintain any level of dignity or even education. They hang onto their titles and lands without demonstrating any fitness for their station. The narrator tells us that Becky has "come into a family of very genteel connexions" and then immediately shows us that Sir Pitt is disgusting and cheap (writing her a note "upon an old envelope" rather than a clean piece of paper), and semi-illiterate (his note is rude and horribly misspelled).