Though it's entirely possible that it might be more trouble than it's worth, I wouldn't mind seeing something programmed in so that if you were somehow blinded or simply could not see a person speaking, rather than simply

"Someone tells you 'kdghklaflkajsflkasjd'"

You would see something more like...

"Someone with a deep voice tells you 'lasdkflskaj'"
or
"Someone with a soft, serene voice tells you 'lkdjflskf'"

Now, these could be done either hardcoded for the different races (maybe just 3-4 different types of voices to help you recognize when you hear "someone." You're blind... not deaf Another way, which allows more free will (a dangerous thing in a text game) would be to create a command so that they could change it to customize their own tells...

"Someone with a deep, booming voice tells you 'alsfsd'"

I dunno, just a thought!