For Hive, I’m seeing a lot of the grapheme “augh” in their names, like Phog[b]o[/b]th, Gar[b]o[/b]k, G[b]o[/b]tra, and so on. Could be related to how “augh” is usually used in something like comic books to express pain, though not sure. Dunno the connection between them and the monarchy-type system they have, but probably more related to the Sword Logic than their class pyramid. Cabal have an “aul” or “aur” sound to most of their names (even the word Cabal), like Gh[b]aul[/b], Ta’a[b]ur[/b]c, Tha’[b]aur[/b]n. If they’re based off of the Roman Empire, some of the names they used back then have the same sound to it. [b]Aur[/b]elia, Caesar (pronounced Kie-s[b]aur[/b]), and so on. Could be the link.

Fallen tend to have audible clicks and hisses in their name as you've noticed Cabal usually (however not always) have a quick break between the name, split up with a comma in between. Mau'ual, Ta'aun, and Tlu'urn are all examples of this. Regardless, most Cabal names sound as guttural as possible even when not using the comma (like Calus, Ghual, Umun) As for hive? It's a little tricky. There isn't really any pattern with hive names outside of ogres, and tend to be a melting pot of names. On one hand you'll have something like Vorlog, while on the other you may get something like Dul incaru

The hive have feudalist names for their units, not sure about Cabal.