Khuzdul is a language from Middle-earth used by the Dwarves. You may encounter PC dwarfs in LOTRO that speak in this language. They will often shout "Khazad ai-menu!" on their way into battle. In order to allow others to understand this great language, there is a basic list of Khuzdul below.
Khazad- Having to do with Dwarves or Dwarf
Ai- are upon or are
Nargun- Mordor; From the root word Narag
Narag- Black or Dark
Khuzdul- the language of the Dwarves
Giglimesh- A hand gesture system used by some Dwarves.