What language is the Elvish language from "The Lord of the Rings" based on, and who created it?

John Ronald Reuel Tolkien, an English writer, poet, philologist, and professor, was the mastermind behind the creation of the beautiful and intricate Elvish languages. He wrote "The Hobbit," "The Lord of the Rings," "The Silmarillion," and many other works set in the fantastical realm of Middle-earth. Tolkien was a linguist and scholar, having a deep passion for languages and the history behind them. His linguistic expertise and love for mythology provided the foundation on which the Elvish languages were built.