From t2twiki
When Aule made the Fathers of the Dwarves, he taught them the Khuzdul tongue for their own use. The Dwarves kept it secret amongst themselves for much of their history, although some diffusion occurred early on, and more recently some outsiders have learned the language.
- Khuzdul can only be learned by non-Dwarves up to 80%.
- The trainer is a person in Belegost who has no pride in his heritage.
