J.R.R. Tolkien associated Quenya with the High Elves.
Quenya is one of Tolkien’s constructed languages and is based partly on the sound and structure of Finnish, along with influences from other languages. In Middle-earth’s history, it is associated with the Eldar and especially with the Ñoldor, whose migration and later return are central to the mythology of the First Age.
Sindarin is another major Elvish language, but it developed as the everyday Elvish tongue of many Elves in Middle-earth. Quenya often has a more formal, ancient, or ceremonial role, much as Latin can function differently from a modern spoken language in historical contexts.
The two languages are sometimes treated as interchangeable because both are Elvish and share related vocabulary. They are distinct languages with different histories, sound patterns, and social uses within Tolkien’s legendarium.