This one is going to be easy, you know free speech when it hits you, when you hear something you really do not like hearing, when the person in front of you has an opinion that is contradictory, even to the degree of offensive to yours. Free speech is not out there for all of us to enjoy, its out there for everyone to use and play with, for the idea that nothing will go unchallenged, that every idea out there will be contested, that any one of us will have a chance to know more because people are not afraid to speak their minds.
Free speech can be easily tracked to show how this is one of the major things that moved our civilization to a point that everyone could contribute, and present the free world its opinion, given that the idea expressed is not calling for the murder or people.
So unless you want to tell everyone that they should kill someone you can enjoy free speech and you can express your mind, and this is so dear to us in the west that we know we must protect it, and the founding fathers understood that at an age without internet and without computers, without a fax machine and fast printers, without RSS feeds and content syndication networks, which means that it is much more important today – and if there is one single thing that is precious to defend today is free speech – do not forget it.
If someone says something you do not like hearing, listen carefully and consider the arguments, wait for your turn to talk but do not close your ears to the claims of the other person, celebrate free speech and defend it always.