I think true freedom of speech is an impossibility of the same vein as freedom of action. Your speech is generally half of an interaction with one or more list

I think true freedom of speech is an impossibility of the same vein as freedom of action. Your speech is generally half of an interaction with one or more listeners and forcing their precipitation is impinging on their freedoms. It is also generally recognized that there is such a thing as dangerous speech but I don't think we even need to start including that category of speech to hit a contradiction - that said we can and should strive to allow as much freedom in expression as possible.