I found this on Equal Treatment for Differently Abled People's facebook page.
This is an awesome sign - I love it - I wish I could carry it around! This happens to me all the time - not funny, but it is funny. You should not do this. You should talk to people normally. Shouting at them won't help anything. If you don't understand what someone is saying to you, just ask them again.
Share this sign with your friends :)