Nothing about "natural right" implies that it enforces itself. Quite the contrary. If rights enforced themselves, they'd be called "laws", surely you're familiar with the law of gravitation.
A right defines what sort of moral or ethical claims you have on other people. If you have the right to free speech, then no one may (lawfully|ethically|morally) use violence against you for speaking. Different people have different ideas on how to protect these rights, of course, but you get the idea.