Khuzdul is the language J.R.R. Tolkien invented for the Dwarves in Middle-earth.
Khuzdul is the secret language of the Dwarves. Tolkien gave it a structure and sound distinct from his Elvish languages, and he associated it with Semitic languages while developing its roots and word patterns. Dwarves generally kept Khuzdul private, so relatively few words appear in the published stories.
The best-known example is the inscription on the West-gate of Moria, which includes the command “speak, friend, and enter.” The Dwarves’ battle cry and personal names also provide glimpses of the language. Tolkien’s broader linguistic method treated invented languages as parts of believable historical cultures rather than as isolated lists of words.
Quenya and Sindarin are Elvish languages, not Dwarvish. The Black Speech was created for Sauron and used in the inscription on the One Ring. These distinctions are important because Tolkien created several languages with different speakers, histories, and functions.