Here's an idea that might help... limit shouts to single words or very short sentences.

Shouting something like "HELP!" or "STOP IT!" or "KILL THEM!" or "OVER HERE!" makes sense... it's the sort of thing one might realistically need to shout. Shouting "HELLO MY FRIEND, HOW ARE YOU DOING TODAY? VERY WELL I HOPE!" does not make so much sense. It's just too long, it starts to sound like a bad slapstick comedy movie or something. Of course that MIGHT encourage some people to try and shout long sentences by splitting them into short fragments and shouting them in sequence, but preventing people from using too many shouts in a short time period because their voice is gone would work well for fixing that as well.

On a slightly  note regarding some of the earlier posts about /tell... I understand that the /tell command itself is not going away, and I agree... but perhaps a version of in-character /tell could be done using some sort of magic spell or item that could be used to allow two-way communication between someone and another person they choose. Would be kind of neat, anyway. Sorry if my ideas make no sense I am kind of a n00b around here