I was recently flicking through a few old bookmarks on my browser and came across Cthulhu Chick’s compilation of Lovecraft’s Favourite Words. As she points out it’s hard to miss his tendency to use obscure and sometimes convoluted descriptives in Lovecraft’s prose. Personally, it’s one of the reasons I enjoy his work. You can’t simply skim over it, you must engage with the writing, which draws you deeper into the story.
All this got me thinking. Would deliberately using Lovecraft’s favourite words undermine or add to a Call of Cthulhu session?
On the one hand it would help position Lovecraft and the specific brand of horror that he evokes. It could also have a welcome nostalgic resonance for players and, if used sparingly, genuinely add to descriptions.
Issues might be that it distracts from the mood, forces a different style on the gamemaster and unnecessarily confuses matters (“What’s brachiate mean?”).
I’m a little ways off running a Call of Cthulhu session any time soon (Eclipse phase is up next on my horizon). But when I do, I’ll take a list of Lovecraftian words and try slipping them in to my descriptions and report back here.

I’d start off by slipping them in slowly to test the waters (and your players vocabulary). I guess the real trouble will start if you use an immense descriptive word to describe something the players should understand. Then they’ll need to break out the dictionary. using it to describe an entity or paranormal effect might be fine if used judiciously.
I think you make an excellent point here Laraqua. Some of the language is a quite arcane. I think too some rapid fire descriptions that drop in a Lovecraftian word here and there and provide a general impression of what nebulous horror the characters face could also work.