J.R.R. Tolkien’s fictional language for the Dwarves was Khuzdul.
Khuzdul is the secret language of the Dwarves in Tolkien’s legendarium. The Dwarves called themselves the Khazâd, and they generally guarded their language from outsiders. In The Lord of the Rings, the inscription on Balin’s tomb includes the name Khazad-dûm, the Dwarves’ name for Moria.
Tolkien gave Khuzdul a distinctive sound and history. The language was taught to the Dwarves by Aulë, the Vala who created them, according to Tolkien’s mythology. Its structure was influenced in part by Semitic languages, especially through consonantal patterns, although it is not a direct copy of any real language.
Khuzdul should not be confused with Quenya or Sindarin, which are Elvish languages. Adûnaic is the language of Númenor, while the Black Speech was created for servants of Sauron. These distinctions matter because Tolkien’s languages are tied to different peoples and histories.