It is striking when you see him many years ago, he looked much more mentally sane. Many people said that the way he speaks is a brillant way to simplify his langage to convince people. I'm really not sure of that. I think he is an empty shell with simple mental reflexes : hate of what he thinks is weak (women, poor people), admire what he sees as strong, grab as much money and pussies as possible, boasts and some others. His supporters can fill him with wathever they want.