In reality though, laws have been limiting speech for hundreds of years, and those laws and judgements are enforced by the government. The idea that it is sacrosanct and is (and should "continue" to be) unabated is already not what happens. The usual example is about shouting bomb in an airport or fire in a crowded movie theatre but those are more about mischief than any freedom to say a thing (you aren't punished for the words alone). However, Libel and Slander laws exist and have for a long long time and are limits on free speech.
I'm not in favor of draconian laws designed to chill debate but it's important to recognize that limits already exist and how we navigate where to draw the line is the key I think.