J.R.R. Tolkien based Quenya primarily on Finnish when creating it for the Elves.
Quenya is one of Tolkien’s constructed languages and is associated with the High Elves. Its sound patterns and grammar were strongly influenced by Finnish, while its vocabulary and historical development were shaped within Tolkien’s broader invented mythology. Tolkien also drew inspiration from other languages, including Latin and Greek.
In the fictional history, Quenya developed from the speech of the Eldar and remained a prestigious literary and ceremonial language. It is sometimes compared with Sindarin, another major Elvish language that Tolkien developed with Welsh as an important influence.
Quenya is not simply “the Elvish language” in every context. Tolkien imagined several Elvish tongues with distinct histories and uses. Khuzdul belongs to the Dwarves, and the Black Speech was created for the servants of Mordor.