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. Your head will go up to the tree. As a portrait photographer, i often use those tricks evoke facial expressions on my models.
Many portrait photographers focused on getting the technical aspects right, and they completely forget about the most important feature of a portrait- who is standing of front of our lens.
I’m not saying that your camera and technique aren’t important. But even when you have the best technique in the world, you will not have a good portrait if your subject feels, and looks, uncomfortable. Not him , her self.
Remember that when you look at someone portrait, in the first sec. we make judgment . So is very important to be in control when we photograph, what we want to show. what reaction we want from the viewer.
Number One, learn how to identify discomfort of your subject. And if you identify, do everything to make it comfortible.
If for someone is hard to express the way you want, Don't talk, just go and show. Show exacly what you mean and what you want your model to do. This is very good way not only to progress with your photo shoot, but also to brake ice. I always look funny when i am showing model how to pose.
NOW go and practice.