Quenya is the fictional language in J.R.R. Tolkien’s legendarium that was inspired largely by Finnish.
Tolkien studied Finnish and admired its structure, sound, and literature. Those influences helped shape Quenya, the language associated especially with the High Elves, or Eldar. Quenya also draws on other linguistic sources, including Latin and Greek, but Finnish is its most frequently identified major inspiration.
Tolkien was a professional philologist, and his invented languages were developed with vocabulary, grammar, sound patterns, and historical relationships. He often created stories and peoples to give those languages a believable history, rather than inventing names only after writing the narratives.
Sindarin is a different Elvish language, influenced strongly by Welsh. Khuzdul is the language of the Dwarves, while Adûnaic is associated with the people of Númenor. Quenya appears in names, songs, ceremonial speech, and poems across Tolkien’s mythology.