According to Reverse Speech theorists the mind embeds reverse messages in ordinary speech. This is not so outlandish a claim — it is known that the brain uses reversal at a very fundamental level in language and perception. Check out this summary of reverse speech results to see some very interesting cases — in particular relating to speeches done by political leaders. I don’t know whether this phenomenon is scientifically legit, but I have been following it for about 6 years. It is quite interesting.