There is no absolute free speech; as with anything abstract, it is either willfully regulated by the laws of humankind and of nature.
To the point of absurdity, the nature of reality limits the ability for a sentient being to voice an infinitely long word (infinite time and energy would be required) or to communicate backwards in time (adhering the the law of entropy, at least as currently understood) or to sentient beings outside of the observable universe (speed of light restrictions). I'm sure one could cherry pick other natural laws to highlight the physical limitation of free speech, but the point is that censorship of a sort is inherent in the real world around us.
And humankind is an incarnation of the known Universe, so it follows that within our own civilization, realistic censorship will occur. The idea that within those constraints that humans are permitted to voice their opinions can never be totally free, and when sensibly defended, regulation of speech can be crafted to improve the world we live in for all. To that end, language that threatens the safety of another being or some part of the world we live in, should be regulated. This might not require outright censorship, but may need to be judged on a spectrum and isolated in extreme situations.
Ultimately, ending all speech that mobilizes violence would be an interesting starting point. For if we could end the bullying, injury and death of all sentient beings, the world could evolve down a more peaceful path. That path could be toward a neartopia devoid of human created suffering. In such a world, all our actions could predominantly work toward building a healthier world for humanity, the environment, and all the living things in it.
The challenge is to institute laws that are enforced fairly among all. If only there were a god to assign this duty. Maybe one day an artificially intelligent agent will fill those heavenly imagined shoes. Until then our laws must serve as an agent to bridge the gap.