a book series that makes use of "anachronistic" language in a way that really feels organic for the period, IMO, is Piratica by Tanith Lee
set in an explicitly alternate universe c. 1810, the first book managed to include the sentence "Well, groovy, thou art a klutz," and make it sound 100% Golden Age of PiracyTM. even though the author used words from wildly different eras, she captured the cadence of 18th/early 19th century working-class/criminal slang so well that I literally just had to look up whether "groovy" was an older word than I previously thought
god those books were so good. I should reread them










