Yes definitely...I rely on reading body language to decide upon the distances i will break or build with a person. I find non-verbal communication far more reliable from whats being spoken. We have more control on our thoughts and less control on our body language ( so the latter reveals the real intentions, emotions). In a way BL is how you live and feel what your saying and it also says what you are not saying ( it can sometimes work against you, example, when u blush =P)
Am I psychic? No, I am just very good at guessing.
i think that the capacity of you reading those signs rely on how much you can project yourself, mirror yourself on the other.
To point out more on the importance of body language, i can refer to animals, speacialy pets( considering that you are in permanent contact with them). Our only way of communicating with them is through BL.
I personaly focus on postures, mouth movement and the eyes
to form an idea of the other person. My own usualy are voice tonalities, a lot of hand gesture, my facial expressions are more under control.
politicians work a lot on their body language