Hum

The Hum was the combined sound of the communications of members of the exogorth species. Though humans could not hear it, exogorths were able to deliver complex messages to one another through the Hum. When it was time for a Clew, an event in which the exogorths would congregate and mate, the Hum changed slightly.

Text and facts from the “Hum” article on Wookieepedia, licensed under CC BY-SA 3.0. Modified for this site.