In the fictional universe of J. R. R. Tolkien, many of the Elves undertook a great migration and built a city upon reaching their destination; in early versions of the mythology, this city was known as Kôr. All those Elves who did not undertake the migration, and consequently did not see Kôr, were known by the Quenya term Ilkorindi, literally "not of Kôr". The same term was applied to their many languages.
"In the course of ages the tongues and dialects of Beleriand became altogether estranged from those of other Eldar in Valinor, through the learned in such lore may perceive that they were anciently sprung from Telerin. These were the Ilkorin speeches of Beleriand."
These Ilkorin Elves spoke three dialects:
- the speech of the Elves of the Kingdom of Doriath, Doriathrin;
- the speech of the Elves from the havens of Brithombar and Eglarest, Falassian;
- the speech of the nomadic Elves living in Beleriand.
Later on (in the early 1940s) Tolkien conceived the name Lemberin for that language, and said about Ilkorin that it "is not rightly a linguistic name, and included the Pereldar, and all who began the march, but did not come to Kór".
So Lemberin became the name for the tongue of the Telerin Elves that remained in Beleriand. Before the coming of the Noldor it was spoken far and wide in Beleriand (save in Ossiriand) and all the names of places, of rivers, woods, fields, plains, hills and mountains were given in this tongue.