As intelligent beings, the Ra'zac and Lethrblaka communicate to each other in their own language, made up of sharp clicks, clacks, clucks, shrieks, chirps and other bird-like sounds. It is unknown what any words in this language are or what they mean, but when Eragon faced the last Ra'zac in Helgrind, the creature clucked and chirped to itself in this language. It could have been uttering a threat or curse in this language, or possibly a secret. Whether the Ra'zac tongue is even pronounceable (or physically achievable) by other species is unknown.