J.R.R. Tolkien based Quenya partly on Finnish. Quenya is one of the major Elvish languages of his legendarium and is associated especially with the High Elves.
Tolkien was a philologist who enjoyed studying how languages develop. Finnish fascinated him through its distinctive grammar and sound patterns, and it became one of the important inspirations for Quenya. Greek and Latin also influenced aspects of the language.
Quenya is not simply Finnish with fantasy vocabulary. Tolkien developed its own grammar, history, and relationship to other languages, including Sindarin. Within the fictional history of Middle-earth, Quenya was an ancient and prestigious language.
Readers sometimes confuse Quenya with Sindarin, the Elvish language more commonly heard in daily use by many Elves in the Third Age. Both are Tolkien’s constructed languages, but they have different histories and roles.