The language of the Ai Naidar has a complex vocabulary system that reflects the social status of the speaker in relationship to the person being addressed. These various modes of address reinforce a person's place in society by constantly defining his relationship to those around him, and thus serve as a perpetual reminder of the person's ultimate role in the Ai Naidar civilization.
The language includes caste markers to show the speaker is above, below, or equal to his listener in rank. To speak without caste markers can cause confusion in the listener (as in "Aunera" of The Aphorisms of Kherishdar), as other Ai Naidar may depend on the speaker's caste-based vocabulary in order to know their position and how to address them in reply.
A language register spoken from a member of a lower caste-rank to a member of a higher one.
A language register indicating a person of very high caste-rank. (Thirukedi uses the highest Implacable to address the Calligrapher in "Thirukedi" of The Aphorisms of Kherishdar.)
Even with instantaneous transit, Kherishdar is too big for us to have a homogenous language. Or it would be, if we didn't have linguists. They go from world to world, notating the local changes and bringing them to the other worlds. They write the common dictionaries. That way a colonist can still talk to someone from the capital.