I heard somewhere that both Osama bin Laden and Saddam Hussein read and speak English (to an extent). They never use it in public, as far as I know, so I’m wondering whether what I heard is true.
Most likely they do speak English. However, because it is a second language, and even if they are fluent, they would never use it in public speaking for various reasons.
First of all, it is very important that your countrymen understand you. How would you feel if Bush decided to speak Arabic at an important conference? Would you be satified and confident listening to an interpreter? I know I wouldn’t. Was what he said interpreted correctly? Did Bush manage to say what he meant?
Second, to prevent misunderstandings - mispronunciation, syntax, inflection, accent, etc. All these things can greatly lessen your impact and muddle and distort the meaning of what you’re saying. All languages have words and phrases that aren’t directly translatable into other languages but which connotate different levels of importance in your language.
It is IMPERATIVE that Saddam disarm!
Saddam WILL disarm!
Saddam MUST disarm!
Saddam CANNOT CONTINUE to manufacture weapons of mass destruction.
We CANNOT ALLOW Saddam to continue…
Saddam CANNOT BE ALLOWED to continue…
etc., etc., ad nauseum.
BUT! Which statement carries the most strength? The most threat? There are many different ways of making the same statement, but each conveys a subtle difference in level of intensity and force. The strongest English phrase may not translate to the strongest Arabic phrase.
It is very difficult to get across allusions in different languages and, most importantly, to different cultures. Even interpretors struggle sometimes, and sometimes they get it wrong. But, at least it’s the interpretor who got it wrong and not the speaker. You can correct the interpretor. It’s much more difficult to correct the speaker. He’s expected to say what he means - as well as mean what he says regardless of the language he’s speaking.
All in all, it’s safer for a speaker to use his native tongue, especially in diplomatic situations.
Saddam does AFAIK. But obviously doesn’t like to, in public. Many national leaders prefer to only talk publicly in their native tongue, as a thing of pride.
Bin Laden visited Oxford in 1971, according to BBC; it is not mentioned explicitly, but I guess from the context that he indeed does speak English.
Saddam attended college in Cairo; it is fairly possible that he learned English there, if he had not done so before.
This site claims to present a genuine interview with Saddam; since my internet access is rather slow and I don’t want to download Real Player first, I don’t want to check this now, but if anybody did and told us I’d be very grateful 
What kind of pride are you talking about? For what mysterious reason would a politician want to speak publically in a foreign language??? (except perhaps when visiting the corresponding foreign country). Even during, say, an international meeting, it seems quite obvious to me that he will want to speak in a language he’s perflectly fluent in, and knows all the shades of, in other words in his own native language. And of course, speaking a foreign language in his own country wouldn’t make any sense.