title_body: How to conjugate "fhtagn" in R'lyehian?
upvoted_answer: Lovecraft probably didn't think about grammar, and we certainly don't have enough material to reconstruct one. Could also be like Sindarin, where Tolkien wrote much, but never released any specification of the language. Quote from the threat you linked: "To my knowledge, we only have the transcription in the Latin alphabet" (comment from Sparksbet).