What is interesting in this movie is obviously the way Henri Fonda is able to convince one after anothher every one of the jury based on one simple paradigm: there is a certain doubt about the fact the kid has not killed his father. Henri Fonda is not speaking much to make his points, he actually rather have the others speaking in order to demonstrate they are wrong.
It also shows clearly how paradigm shape the way people make their judgement, far more than actual facts, no matter what they say.
A very interesting movie to watch and rewatch to analyze the whole script and how the debate evolves.