Khuzdul is the fictional language J.R.R. Tolkien created for the Dwarves of Middle-earth.
Khuzdul is the secret language of the Dwarves, who call themselves the Khazâd. Tolkien constructed it with a distinctive root-and-pattern structure influenced by Semitic languages, especially in the way consonantal roots support related words. Dwarves generally guarded Khuzdul from outsiders, so comparatively little of it appears in the published stories.
The best-known Khuzdul battle cry is “Baruk Khazâd! Khazâd ai-mênu!”, associated with the Dwarves’ identity and martial tradition. Tolkien also gives Khuzdul place-names, including Khazad-dûm, the great underground city later called Moria by the Elves.
Khuzdul is not Quenya or Sindarin, which are Elvish languages. It is also different from the Black Speech, which Sauron devised for the servants of Mordor. Tolkien’s languages therefore identify cultures as well as provide vocabulary.