The first Elvish language J.R.R. Tolkien developed in detail was Qenya.
Tolkien began developing Qenya during the 1910s, using it as an early form of the language later known as Quenya. Its creation was part of his lifelong practice of inventing languages with internal histories, relationships, and changes over time. Qenya was influenced especially by Finnish, while Tolkien also drew on other languages for different linguistic effects.
As Tolkien revised his mythology and linguistic systems, the language’s form and name changed. The later form is usually written Quenya and is associated with the High Elves of Aman and Middle-earth. This makes Qenya an important early stage in the development of Quenya rather than a wholly unrelated language.
Sindarin developed as a separate Elvish language with strong Welsh influence. Telerin is another language within Tolkien’s Elvish family, while Adûnaic is the language associated with the Númenóreans.