The secret Dwarvish language in J.R.R. Tolkien’s legendarium is Khuzdul.
Khuzdul is the language created for the Dwarves of Middle-earth. Tolkien gave it a sound and structure distinct from the Elvish languages, drawing inspiration from Semitic languages while making it part of his own fictional linguistic history. The Dwarves traditionally keep Khuzdul private and generally use the languages of neighboring peoples when dealing with outsiders.
Only a small amount of Khuzdul appears in Tolkien’s published writings. Names and phrases such as Khazad-dûm and ‘Baruk Khazâd! Khazâd ai-mênu!’ provide some of the best-known examples. The language’s limited presence reinforces its secretive cultural role.
Quenya and Sindarin are Elvish languages, not Dwarvish ones. Adûnaic is associated with the Númenóreans. These languages belong to different peoples and linguistic traditions within Tolkien’s mythology.