The Elves of Rivendell commonly speak Sindarin in J.R.R. Tolkien’s legendarium.
Sindarin is one of Tolkien’s major Elvish languages and is associated especially with the Sindar, or Grey Elves. It became the everyday Elvish language of many Elves in Middle-earth, including those encountered in Rivendell and Lothlórien.
Quenya is another major Elvish language. Tolkien modeled aspects of Quenya on Finnish and Sindarin partly on Welsh, but both are invented languages with their own histories, sound systems, and vocabulary. Sindarin should not be confused with Khuzdul, the secret language of the Dwarves, or the Black Speech of Mordor.
The films popularized several Sindarin phrases, but Tolkien’s linguistic work extends far beyond the words spoken in the adaptations. His languages were connected to the historical development of the peoples who used them.