The film includes many classic scenes of comedy - especially the interplay between Hynkel and Napaloni - but it also has serious undertones. You must remember that this film was made when Adolf Hitler was in power and World War II raged across Europe. It was a brave film to make at the time, though upon learning later of the horror of the concentration camps, Chaplin confessed that he wouldn't have made the film with this knowledge (the same thing Hergé said about his Quick and Flupke/Hitler cartoons).
The speech that ends the film is quite famous and even controversial - for some it is overly sentimental, for others it is a real message of peace from a man that the whole world would listen to. Chaplin was asked to repeat the speech on national radio. It may seem a bit dated now in it's style, but it's still sadly apt for the world today.
The plot before hand concerns an innocent Jewish barber (Chaplin) who ends up being mistaken for the Ptomanian dictator Adenoid Hynkel (also Chaplin). He soon finds himself dressed in the fuhrer's outfit, on a platform facing 'his' army, and expected to make a rousing speech to spur on the evil genocide and invasions.
"I'm sorry, but I don't want to be an emperor. That's not my business. I don't want to rule or conquer anyone. I should like to help everyone if possible - Jew, Gentile - black man - white.
The way of life can be free and beautiful, but we have lost the way. Greed has poisoned men's souls - has barricaded the world with hate - has goose-stepped us into misery and bloodshed. We have developed speed, but we have shut ourselves in. Machinery that gives abundance has left us in want. Our knowledge has made us cynical; our cleverness, hard and unkind. We think too much and feel too little. More than machinery we need humanity. More than cleverness, we need kindness and gentleness. Without these qualities, life will be violent and all will be lost.
The aeroplane and the radio have brought us closer together. The very nature of these inventions cries out for the goodness in man - cries for universal brotherhood - for the unity of us all. Even now my voice is reaching millions throughout the world - millions of despairing men, women, and little children - victims of a system that makes men torture and imprison innocent people. To those who can hear me, I say: 'Do not despair.' The misery that is now upon us is but the passing of greed - the bitterness of men who fear the way of human progress. The hate of men will pass, and dictators die, and the power they took from the people will return to the people. And so long as men die, liberty will never perish.