That's the problem with many people's view of "free speech" - It's NOT:

Burning a flag
Breaking a window
Clicking a button
Submerging a crucifix in a bucket of urine (and calling it "art")

or any other activity that DOESN'T involve opening one's mouth and speaking!

The founding fathers understood that "speech" means "speaking" - that's why they also enumerated rights like Freedom of the Press, Freedom of Assembly, etc. - because "Freedom of Speech" doesn't cover those other things.

The way "Freedom of Speech" is bandied around these days is a typical misdirection tactic - change the meaning of the words in a law, and you can change the law!

It wasn't meant to be that way.

PS: I agree that in the case of a mute person, written communication, sign language, etc. should be considered HIS form of free speech - however, this sort of thing more properly decided on a case-by-case basis, just as we wouldn't expect a wheelchair-bound person to abide by the "Walk/Don't Walk" traffic signs by getting out of his wheelchair to WALK across the street.