Fact is, that still pictures can't capture voices. I believe that non-verbal communication shows more human expression than talk. Our body don't know how to lie. Imagine yourself being so sad and have a smile on your face. Hmmm ? Hard thing to do when real emoticons are in progress. But imagine yourself shouting, [ Hey Thomas come come down from this tree !!!!! ] your body will automatically change the shape, your posture will change , your facial impression will change too