title_body: What is R'lyehian based on?
upvoted_answer: Ostensibly, the transcription we have of R'lyehian is supposed to be a crude attempt to represent utterly inhuman sounds with the Latin alphabet. Most of what I can find on R'leyhian claims that it attempts to be an un-Earthly language: it does not distinguish between parts of speech, for example. It seems likely to me that Lovecraft at least attempted to invent a fully a priori conlang here.
  
  I've found a Quora answer claiming the language "has basic elements of Welsh and German glottals," but it's unclear what exactly that means and where they got that information from.