Studying attested phrases is a great way of learn Tolkien's languages. We currently have 66 phrases in our database, and 16 of them are neologisms.
Sindarin is the main Eldarin tongue in Middle-earth, the living vernacular of the Grey-elves.
Quenya, also called High-elven, is the language of the Quendi, the elves of the West. It was brought to Middle Earth during the exile of the Noldor.
Telerin is the language of the Teleri who first dwelt in Tol Eressëa. It is the language of the sea elves.
Black Speech was devised by Sauron in the Dark Years, and he desired to make it the language of all those that served him, though he failed in that purpose.