They awoke at Cuiviénen on the continent of Middle-earth, where they were divided into three tribes: Minyar (the Firsts), Tatyar (the Seconds) and Nelyar (the Thirds).
The Tolkien scholar Tom Shippey writes that The Silmarillion derived from the linguistic relationship between the two languages, Quenya and Sindarin, of the divided Elves.
[1] He created a family of invented languages for Elves, carefully designing the differences between them to reflect their distance from their imaginary common origin.
[2][3] In Tolkien's legendarium, the Elves awoke at Cuiviénen, a bay on the eastern side of the Sea of Helcar, on the continent of Middle-earth, where they were divided into three tribes: Minyar (the Firsts), Tatyar (the Seconds) and Nelyar (the Thirds).
[5] Those of the Teleri who reached Beleriand by the Great Sea but chose not to cross to Valinor were later called the Sindar (Grey Elves); their language was Sindarin.
[5] Those who chose to remain behind and populated the lands to the north-west of Beleriand were called the Mithrim or Grey People, giving their name to the region and the great lake there.
[T 4] Those of the Teleri who refused to cross the Misty Mountains and stayed in the valley of Anduin were called the Nandor (Those [Elves] who turn back).
Hearing of the peaceful territories of King Thingol, Denethor, son of Lenwë, collected as many of his scattered people as he could and finally ventured westward over the Ered Luin into Ossiriand.
[T 6] Their small clan was founded by Imin, the first Elf to awaken at Cuiviénen, with his wife Iminyë and their twelve companions: they broadly correspond to the Minyar.
[T 7][T 8] After the War of Wrath that ended the First Age, the greater part of the surviving Noldor and Sindar (mostly mingled into a single people) returned into the West to dwell in Tol Eressëa.
The rest remained in Middle-earth throughout the Second and Third Ages, entering the realm of Mirkwood of the Wood Elves or establishing the kingdoms of Lindon, Eregion, Lothlórien and Rivendell.
[T 3] After the Separation the Avari became divided even more than the Eldar, though little of their history became known to the Elves and Men of the West of Middle-earth, and they barely feature in the legendarium.
[5] Shippey suggests that the "real root" of The Silmarillion lay in the linguistic relationship, complete with sound-changes and differences of semantics, between the two languages of the divided elves.
This picture of increasing separation is analogous to the progressive decline and fall in Middle-earth from its initial perfection, of which the Sundering of the Elves is a major element.
Tolkien thus intended ancestry to be a guide to character; the differences between the various Elvish languages mirror both the Sundering and the events of The Silmarillion.