Sindarin is the most widely spoken Elvish language in J.R.R. Tolkien’s Middle-earth during the period of The Lord of the Rings.
Tolkien based Sindarin partly on the sound and historical development of Welsh. In the fictional history, it developed from an older Elvish language and became the everyday language of many Elves in Beleriand and later in Middle-earth.
Quenya is the other major Elvish language readers often confuse with Sindarin. Quenya had a more ceremonial and scholarly role in much of the later history, while Sindarin was commonly used in conversation among many Elves. Tolkien created detailed sound systems, vocabularies, and grammatical structures for both.
Names such as Galadriel, Celeborn, and Moria are associated with Tolkien’s constructed linguistic world, although not every familiar fantasy name belongs to the same language.