[sometimes_all]

The Call of Cthulhu seemed to have a bit of language construction and world-building, if you are into that. But my knowledge of Lovecraft lore is limited, so I wouldn't know all details; I just read his short stories from Standard eBooks a few months ago, which was my first exposure to his work.

I'm sure S. T. Joshi might have a bit to say about the topic. Personally speaking from very limited exposure and knowledge of language games, and me not being from an environment which has European language roots, I might have missed quite a bit of such easter eggs in the atmosphere and writing. Like, for example, your comment prompted me to find out what "rue d'auseil" (from The Music of Erich Zann) meant, I didn't bother to find out until today.

I do recommend rereading Lovecraft in English either way, since you never know what gets lost in translation!