Which language does Tolkien call the Black Speech of Mordor?

Tolkien calls the language used by Sauron and associated with Mordor the Black Speech.

The best-known surviving example is the inscription on the One Ring: “Ash nazg durbatulûk,” beginning the verse that describes one Ring ruling the others. Tolkien created the Black Speech as a language devised by Sauron for the servants of Mordor.

It is distinct from Quenya and Sindarin, the major Elvish languages in Tolkien’s mythology. Westron, meanwhile, is the Common Speech used by many peoples in The Lord of the Rings and is often represented by English in the text.

Tolkien did not provide a large, complete vocabulary for the Black Speech. Much of its modern recognition comes from the Ring inscription, which appears in The Fellowship of the Ring and is connected to the history of the Rings of Power.