Khuzdul

The secret language of the Dwarves, passed to them by Aule, their creator. In the course of time, Khuzdul went through so few changes that even in the Third Age Dwarves from different tribes could communicate without any difficulty. Throughout its history, Khuzdul remained linguistically isolated from other languages, only the noblemen of Gondor incorporated some of its elements into their tongue. As to the Elves, the only one who actually troubled himself with studying Khuzdul was Curufin, who greatly desired the friendship of the Dwarves of Nogrod. As the legends tell, Pengolod came to Moria with the sole purpose of studying Khuzdul.

Khuzdul is called the secret language because the real dwarf names were in Khuzdul, and the Dwarves never revealed them to other races. The names that we commonly know – like Gimli and Thorin – were mere aliases, nicknames and substitutes for real names. The Noegyth Nibin, though, did not value secrecy quite as much and did not conceal their Khuzdul names.

Apart from Khuzdul, the Dwarves also made wide use of iglishmek – the tongue of gestures.