Final answer:
J.R.R. Tolkien, a British author, invented languages such as Quenya, Sindarin, and The Black Speech for his Middle-earth novels.
Step-by-step explanation:
The British author who invented languages such as Quenya, Sindarin, and The Black Speech is J.R.R. Tolkien.
Tolkien was an English writer, poet, and philologist, best known for his fantasy works, including The Hobbit and The Lord of the Rings trilogy. As a linguist, he developed complete fictional languages for his fictional world, Middle-earth.
Quenya and Sindarin are the most well-known of Tolkien's invented languages and are spoken by the elves in his books. The Black Speech, on the other hand, is a language created for the evil characters in his novels, such as Sauron and his orc minions.