Quenya is the Elvish language that J.R.R. Tolkien based mainly on Finnish.
Quenya is one of Tolkien’s principal Elvish languages. Its sound and grammar were strongly influenced by Finnish, while its vocabulary and history were developed within Tolkien’s fictional mythology. Tolkien also drew on other languages, including Latin and Greek, in designing his linguistic systems.
Within Middle-earth, Quenya is associated especially with the High Elves and with an older, formal literary tradition. Sindarin, another major Elvish language, became more widely spoken in much of Middle-earth. The two languages are related in Tolkien’s internal history but are not interchangeable.
Tolkien was a professional philologist, so his invented languages were designed with historical development, sound changes, and related forms. Quenya is not simply a substitution cipher for Finnish. It has its own vocabulary, grammar, and fictional history, which makes it a constructed language rather than a version of Finnish.