Quenya is the language J.R.R. Tolkien created for the Elves of Valinor. It is one of the best-developed languages in his legendarium and is associated especially with the High Elves, including the Noldor and Vanyar.
Tolkien based Quenya partly on the sound and structure of Finnish, while also drawing on other linguistic traditions. He developed vocabulary, grammar, pronunciation, and historical changes rather than inventing only isolated words.
Quenya was not the everyday language of all Elves in later Middle-earth. Sindarin became more widely spoken there, particularly among the Sindar and many Elves of Beleriand. Quenya retained a formal, literary, and ceremonial role, somewhat like a classical language.
The distinction between Quenya and Sindarin is a common source of confusion. Both are Elvish languages, but they belong to different historical and cultural contexts. Tolkien’s linguistic work came before and helped generate much of the mythology in which these languages appear.