The Great Dictator was Chaplin’s first film with dialogue. Chaplin plays both a little Jewish barber, living in the ghetto, and Hynkel, the dictator ruler of Tomainia. In his autobiography Chaplin quotes himself as having said: “One doesn’t have to be a Jew to be anti Nazi. All one has to be is a normal decent human being.”

Chaplin and Hitler were born within a week of one another. “There was something uncanny in the resemblance between the Little Tramp and Adolf Hitler, representing opposite poles of humanity, ” writes Chaplin biographer David Robinson, reproducing an unsigned article from The Spectator dated 21st April 1939:
“Providence was in an ironical mood when, fifty years ago this week, it was ordained that Charles Chaplin and Adolf Hitler should make their entry into the world within four days of each other….Each in his own way has expressed the ideas, sentiments, aspirations of the millions of struggling citizens ground between the upper and the lower millstone of society. (…) Each has mirrored the same reality – the predicament of the “little man” in modern society. Each is a distorting mirror, the one for good, the other for untold evil.”

Chaplin spent many months drafting and re-writing the speech for the end of the film, a call for peace from the barber who has been mistaken for Hynkel. Many people criticized the speech, and thought it was superfluous to the film. Others found it uplifting. Regrettably Chaplin’s words are as relevant today as they were in 1940.

Source: https://www.charliechaplin.com/en/synopsis/articles/29-The-Great-Dictator-s-Speech