It is an unfortunate fact that when talking about him, it is all too easy for the tongue to slip and to say a “b” where the “s” ought to go in “Osama”. This is most annoying to me, but nevertheless, I–and many people I know–have made this error. Salon has a good article on this, and I agree with the claim that this is all the “b” in “bin”‘s fault.
What is particularly troubling about this little mistake is that people rarely used to call bin Laden “Osama”. Everyone called him “bin Laden”. He was the most infamous bin Laden in the world, so no need to say “Osama”. After all, there’s rarely a need to specify, for instance, that we are talking about Adolf Hitler, and not some other Hitler, and so we drop his first name.