Although to the surface-worlders it may seem that Druhau are all the same-- perpetuated by the fact that they are rarely seen--Druhau vary as much by region and city-state as any Asrani or Meirani (Surface-dwelling Eldar.)

Asrani - bright kin - valari, sometimes draihari if being xenophobic
Meirani - half kin - typically used for draihari
Durani - dark kin - rarely used, usedto differentiate a group of druhau from a group of non-druhau
Druhrani - under-kin
Dur - root word for druhau, means dark
druh could mean under and dru is like a simplified version that can mean dark or is a dialectical shift

they have a nonverbal language
garafalar = clawspeak
spoken in hand gestures supported by sighing and hissing