You must realize that the language used in the US Constitution is very exceptional in international terms. It affirms a non-restricted freedom of speech in a way that cannot be misunderstood: the only real way to subvert it is if you can get away with completely changing the meaning of the words used in it. This is a very strong barrier to tyranny. Don't make the mistake of assuming that there are any other nations in the world that enjoy this same level of protection.
The language used in European freedom of speech laws, as an example, comes with qualifications and exceptions built-in. Consequently the seed of tyranny is also built into these laws. They can never be understood to be any sort of guarantee of actual free speech but need to be seen as a (strong) statement of intent more than anything.
(This is one of the reasons I personally am completely indifferent to the whole EU project: they only serve more of the same tripe that is already in place. Had the EU proposed an actual strong freedoms-centric constitution it would have been different, but they didn't.)