This question, like the earlier one about freedom of choice, is very unclear. If you could give us a better idea as to what you want to know, we could give you better answers.
I think that Guy Montag and Faber and Clarisse McClellan would probably see free speech about the same way we do today. All three of these people wanted to be free to have their own thoughts and, I think, to express whatever ideas they had to anyone else.
Captain Beatty might see free speech differently. I do not think he would really value it. Instead, he would think that we should be free from hearing other people say things we don't like.
Mildred Montag would probably not think about it much at all. She probably sees free speech as her right to talk to the "family" on the parlour walls.