Silent Movies and the use of Body Language

Body language is extremely important to animation - it tells you about the character, what they are thinking, feeling, what they are doing and makes the scene much more clear. This is usually exaggerated in animation for different effects, especially when it comes to comedy. Reference is extremely important when it comes to  looking at body language and what your character is trying to say - you can create the movement yourself with whatever emotion you are going for, and then exaggerate the parts of that pose that really convey what it is about. Disney did this with many of their films, even shooting the whole film as live action before going in and animating. This lets them make sure that the characters are moving like a character should, and expression their emotions how they should do.

You also need to consider the audience, and what cues they will understand - not everyone interprets things in the same ways, especially between cultures, although when an animation has sound and music to back it up then this is less of a problem, since the context is already there.

Source: http://westsidetoastmasters.com/resources/book_of_body_language/chap1.html

Silent films do not have the audio context to back it up, so everything has to be much more clear and concise. This makes it excellent reference for animators and deciding on how to make their character animation clearest.

Charlie Chaplin, was a master of this, using over exaggerated facial expressions and body language to add a sense of humor around normal movements. He could also put more exaggeration on the important movements and expressions though, at points where it was the most important to the story.

Chaplin was even studied by Disney animators for his timing and interaction with the audience. There is no doubt in his actions about what is happening an what his character is thinking - even what the character is like, and the atmosphere of the scene despite the lack of colour, making a clear and entertaining performance.