... definitely de Saussurean, now that I think about it, namely the fact that I haven't read him myself yet (too many other books to read for school we've never been assigned de Saussure himself), but father did when I was maybe 17. He got all excited about parole as "that which is spoken", and impressed the impression of it on me before I encountered the full theory, because it made so much sense.
Hm. Was structuralist theory of language something widely accepted and worked with in Lewis' and Tolkien's time and place, or is it me impressing my own experience on it? It's kind of assumed as the ground to build on at my own school; structuralism always had a big influence in Czech lands (Prague school).