While sound and dialogue are integral parts of film making, lesser films which fail to adequately exploit the visual possibilities of the medium could just as easily play on the radio.
Charles Chaplin was a master of visual storytelling and resisted the trend toward sound pictures well after sound technology had been adopted in Hollywood.
Here are the famous opening scenes from Chaplin's City Lights:
Chaplin seemed to relent in in the 1936 film, Modern Times. Yet even then the Tramp uttered only gobbledygook.
In the BFI Film Classics book Modern Times, author Joan Mellon writes: "For the first time on the screen, Chaplin's voice is heard, if only in mock-Italian gibberish...The song may be synchronized but it doesn't make any sense. Yet through pantomime, finger to his lips, slapping his rear end, circling his hand on his hip, moving his arms together, the tramp tells an entire story. You don't need words, Chaplin's final pantomime insists." (p. 63)
Two contemporary films exemplify fine examples of visual storytelling. One is Paul Thomas Anderson's 2007 film, There Will Be Blood. While the entire film relies heavily on visual language to tell the story, the opening fifteen minutes are completely devoid of dialog. Here's the trailer.
And here's the trailer from Steve McQueen's remarkable 2008 debut film, Hunger which was just released on DVD.
Coming full circle, here's the link to a fine article from the British Film Institute on Hitchcock's visual storytelling methods.