Quenya is the language Tolkien invented and developed most extensively for the Elves of Valinor.
Tolkien created Quenya as part of his lifelong project of constructing languages for Middle-earth. It is associated especially with the High Elves, including the Ñoldor, and is presented as an ancient, prestigious language in the legendarium. Its sound and grammar were influenced by languages such as Finnish, Latin, and Greek.
Quenya is not the same as Sindarin. Sindarin became the more commonly spoken Elvish language in much of Middle-earth during the Third Age, while Quenya often remained a formal or literary language. Tolkien revised both languages repeatedly as his mythology developed.
The language appears in names, poems, songs, and ceremonial phrases across Tolkien's writings. Its detailed vocabulary and grammar helped make Middle-earth feel historically layered. Tolkien's linguistic interests came before many of the stories, so the languages were not merely decorative additions to an already finished world.