In the beginning, there was silence. A little over 130 years ago, the limitations of the analog technology forced the moving streams of images we call movies to silence. Yet silent movies were never a choice, much less a genre. Even back when the sound-less film was, literally, the only technology in town, the art of cinema was not meant to be mute. Theaters hired piano players and even live actors to make up for the missing dimension. Elsewhere, where they couldn't afford hired audio contractors, it was left to the attendance to provide sounds.
The so-called silent movies were indeed highly participatory activities; they were social events which allowed audiences to become the voices and the noises of the movies they were witnessing. It could be argued that the crowd-sourced, collaborative noise which silent cinema enabled -- and even encouraged -- made each screening a truly inclusive event: an experience so unique, in fact, that it could never be replicated.
In digital storytelling, the sound is a critical component that cannot be replaced. To a degree, the sound of the spoken words can be mirrored on screen using printed words, like subtitles or interstitials. Otherwise, nothing can take the place of the music, the sound effects, the tones, the atmosphere, the presence and the noises that make videos what they are. The audio dimension ensures that there is a proper three-dimensional context and that there's breathing space. Sound soaks the moving images in an environment that makes the experience as human, dynamic, and fluid as can be.
That being said, it is a cruel irony of the modern way of life that the majority of videos are consumed without sound. We watch most videos on a tiny phone, equipped with a tiny speaker -- one we can barely hear from 2 feet away. We barely pay attention anyway, unless the movie jumps out at us. We watch videos while we drive. We watch videos while we eat, drink and talk. We watch videos while we exercise. We watch videos while we watch TV. We watch videos in between chats and other activities, in spite -- or maybe because -- of the fact that we're already busy. This is both what we do and how we do it.
Does that mean that you can afford to skip the audio dimension and put all your chips on silence.
Rule no. 1: Assume that 80% of your audience is deaf.