J.R.R. Tolkien gave the dark language used by Sauron and his servants the name Black Speech.
The Black Speech was created by Sauron during the Second Age to serve as a common language for his servants. Tolkien presents it as a harsh language associated with Mordor, domination, and the power of the Dark Lord.
The best-known surviving example is the inscription on the One Ring: “Ash nazg durbatulûk,” part of the Ring verse. The inscription is written in Tengwar script, but the language of the words is Black Speech. Script and language are therefore not the same thing.
Readers often confuse Black Speech with Orcish, but Tolkien’s writings use these terms differently. Orcs spoke many related or local forms, while Sauron intended the Black Speech as a unifying language for his forces.