[Lurking Libertarian]

Unless there's charges being brought against somebody, in which case he cannot say anything even in his own defense.

That's not the law. If there are charges against you, you are entitled to deny them.

Most lawyers advise clients under criminal investigation not to talk too much, but that's purely for tactical reasons: if the client denies the charges and says something that's later proven false, that false denial may be admissible in evidence; and if the client has some strong evidence that the prosecutor doesn't know about, the lawyer may want to surprise the prosecutor at trial. But it is very common to say, at least, something like "I deny these accusations and look forward to clearing my name at trial."

[Darksheare]

I didn't say it was the law now, did I?