Quenya is the fictional language J.R.R. Tolkien created for many Elves and based largely on Finnish. Tolkien developed Quenya as part of a broader family of Elvish languages, giving it grammar, vocabulary, historical change, and different regional forms.
In Tolkien’s linguistic history, Quenya was associated especially with the High Elves, including the Ñoldor and Vanyar. It functioned as a language of lore and ceremony in many later contexts, rather than being the everyday speech of every Elf in Middle-earth. Its sound and structure helped Tolkien create the impression of an ancient, highly developed language.
Sindarin is the other major Elvish language frequently encountered in The Lord of the Rings. Tolkien based Sindarin chiefly on Welsh, while Quenya drew strongly on Finnish and also reflected other linguistic influences. Quenya is therefore not simply another spelling system for Sindarin; they are related languages with distinct histories and features.