Kornoldorin, "Noldorin of Kôr", or Korolambë, "Tongue of Kôr", was the language of the Noldoli in Valinor. The Noldor used it beside Qenya, but unlike Qenya, it changed fast as the Noldor devised new words and structures by themselves.
In the stage of the later Silmarillion, Tolkien rearranged several details: the language described as Old Noldorin is taken by the Noldorin dialect of Quenya, and the language called Noldorin was renamed "Sindarin" and took the place of the vernacular Ilkorin in Beleriand.
Old Noldorin belongs to a chronological and phonological stage which Sindarin would normally also have passed through, specifically a stage when final vowels still existed, and consonants did not undergo lenition yet; however this stage is not named or described by Tolkien other than some example etymological reconstructions. Fans name this phase "Old Sindarin".
- J.R.R. Tolkien, Christopher Tolkien (ed.), The Lost Road and Other Writings, "Part Two: Valinor and Middle-earth before The Lord of the Rings, V. The Lhammas"
- J.R.R. Tolkien, Christopher Tolkien (ed.), The Lost Road and Other Writings, Part Three: "The Etymologies"
- J.R.R. Tolkien, Christopher Tolkien (ed.), The War of the Jewels, "Part Four. Quendi and Eldar"