There are some ways to determine what the person is saying through the use of his body. First of all the person is using hand gestures or moving his body on a certain way when conversing, there is a good indication that he is reacting to something that has been said.
Years ago I read books by the anthropologist Desmond Morris, on how Italians use their body when speaking and others on dealing with difficult people and have come to conclude that there is a lot of truth in what was written. Allow me to mention some of the underlying causes for people reacting the way they do.
Firstly when a person is shy and has difficulty meeting a person or is unsure about what he has to say, he may glance away from the individual or look down. There may be other causes behind the glancing away and that may be saying something, which is untrue. This would explain why someone would avoid looking at someone else in the eyes if something has been exaggerated or he had lied.
After teaching classes for many years, I have learnt that some students who are uncomfortable speaking especially if they are self-conscious of their accents and diction are likely to cross their legs and arms. This is a defence mechanism as the body is showing the teacher that the student does not want to willingly open up to the teacher and talk about himself. Talking about himself in public is a good cause for new students to clam up and turn defensive especially if they are shy. Naturally the crossing of the arms has been shown when a person disagrees with another's opinion
One should always consider the facts behind social encounters before coming to any quick judgement about what a certain body language means. It is too easy to generalize and say that all cross-legged people are defensive or cross-armed people are diffident.
