(here is where I start to go OFF)
Lucas is a hack. There are no "languages", at all, canon or otherwise, in Star Wars. What George did was make funny transliterations for comedic effect. It isn't even like the faux-Klingonese (or klingonaase) that James Doohan crafted for the first "Star Trek" film, that was then shoehorned into TNG canon.
Tolkien only really started writing fiction as a vehicle for his invented languages; while not exactly true, the waaaaay-geeky Tolkienophile joke is "at 7, he knew 7 languages; at 21, he knew 21".
Sindarin is Gaelic in syntax and pronunciation; Quenya is Finnish (hah!). Sindarin is the common tongue of all Elves in Middle-earth; Quenya is the Latin of Elves, and only commonly spoken in the Uttermost West. In his notes, Tolkien remarked that Sindarin is more highly evolved, while Quenya is more primitive (there are even notes about "proto-Quenya", which is like Sanskrit) - and so Sindarin was more interesting to him to fiddle with. That's why there was enough in the corpus to allow David Salo to do his linguistic work for PJ's films.
(and now, I stop typing and go back to work)
See? Start me on Tolkien, and you'll all stick knives in your eyes to escape the deluge.