Not sure if it has come up in the past - but it is kind of a close thing to think of...
In the past some of the - well... lets call them non-human-speech factions have sometimes struggled to convince the unaware of their non human origin - mainly because human speech simply is necessary for communication.
While the Nomads have consented on using the asterix **** a lot - AI had problems differentiating themselves from that. I have seen some using ++++ - others ----- and so on.
But is there a downside of adding a chat colour based on the ID you have mounted?
Nomads might be Purple or Pink by default when they chat
AI might be grey
etc.
They can still use their own patterns if they insist on it - but no matter what - other players would instantly know what the other person is all about - and reactions might be a little less awkward.
(or give them the unique console command to use a specific colour if they want to)
postscript: i have been out of touch with the game for too long - maybe the chat uses too many different colours already - so its no good alternative.
no idea if different fonts could be used - that would be even better than colour (like "system" font for AI and some sort of "handscript" for nomads or so - something fluent and natural