J.R.R. Tolkien based Quenya largely on Finnish.
Quenya is one of Tolkien’s most developed Elvish languages and is associated especially with the High Elves. Tolkien admired the structure and sound of Finnish, and Finnish influence can be seen in Quenya’s grammar and vocabulary. He also drew on Latin and Greek, among other languages, when developing his linguistic ideas.
Sindarin, another major Elvish language, was influenced primarily by Welsh rather than Finnish. Tolkien designed these languages as part of a larger mythology: the languages changed over time and had relationships, histories, and regional varieties.
Quenya is sometimes called “High-elven” or “the ancient tongue.” It appears in names, poetry, ceremonial speech, and phrases throughout Tolkien’s writings. Because Tolkien revised his invented languages repeatedly, the surviving Quenya material is extensive but not a complete modern language in every grammatical detail.