Here are some of the references in that passage that I would have had difficulty explaining before reading this book, and some I still cannot define: the GO among the “goes!”; the Stews; Mother Dish-up’s; for a single darkey; the Hells; the Prime Ones at Tattersal’s; the Fives-Court; the Fancy; and the significance of Don Giovanni and Signor Antonelli in (apparent) reference to gambling.

This meaning of “Hell” is defined in the linked dictionary: “a fashionable gambling house.” I learned “the Fancy” when I read this and other books by Pierce Egan, as it’s a term he often used to mean boxers. While I understood immediately that the “class of females” in the Theatres meant prostitutes, I might not have picked up on that if I hadn’t read this and other books from the Regency period.

I second all of those. I'm American as well, and they're all similarly gibberish to me.

As a non-native reader it seemed pretty clear to me as well. I guess knowing some French and having read a lot of fantasy novels helps.