The face speaks
Facial expression translates someone's deepest thought or feeling into something easily readable by any observer. On the other hand, if we think about our physiological growth, we have all developed first hearing, then listening, then touch, then listening, followed by sight and sensing. They are all senses able to make us interact and recognize in the world what we like and what we don't. It is no wonder that a child in diapers smiles at a smiling face and starts crying in front of an angry face.
In essence, we learn to react first to what we see and feel that to what we "listen". In fact, language is a layer of communication that has evolved subsequently to hearing and that requires the support of the grey matter of the brain, while "feeling" is part of the reptilian part of our brain: an instinct, a sixth sense.
When we receive a verbal message we always interpret it accompanied by the different non-verbal languages that we elaborate unconsciously, that is what we report as "sixth sense". In reality it is not an abstract or paranormal perception, we have simply decoded the signals of the face on the basis of our previous experience.
This step is fundamental to achieve effective communication, and as you may have guessed it requires a path of personal growth and not just voice improvement.