J.R.R. Tolkien gave the language of the Elves based largely on Finnish the name Quenya.
Quenya is one of Tolkien’s best-developed Elvish languages. He designed its sound and grammar as part of a larger fictional history, rather than creating it only as a collection of fantasy words. Finnish was a major inspiration, and Tolkien also drew on Latin and Greek among other linguistic influences.
Within Middle-earth, Quenya is associated especially with the High Elves, including the Ñoldor and Vanyar. It functions in the mythology as an ancient and prestigious language, while Sindarin is more commonly spoken among many Elves in the Third Age.
Quenya is sometimes called “Elvish,” but Tolkien created several Elvish languages, so that label is too broad for a precise answer. Quenya is also distinct from Sindarin, which Tolkien developed with a different historical and linguistic profile and whose sound was influenced in part by Welsh.