yes it's a science named the synergology the body language is more important and expressive than the language talked..try to observe around of u and u'll know how much it's significant

yes of course, it is the sings we send to our interlocutor when we are speaking with him/her and show what we are feeling even better than our words. It is spoken by our body posture, the way we are moving our arms, the position of our head, even the direction we see while speaking, so, it can be quite a giveaway of information we want to keep if the other person can understand ( well, most of it is clear to everyone, so...) !!!

yes we all use body language, in our gestures, eye contact, facial expression and so on. Body language communicates more meaning than speech. On italki we don't always see it so meaning can be lost. However, some people are better at interpreting body language than others. So this means that communication can be at different levels depending on whether you recognise body language or only respond to speech. Some people are really good at responding to body language, others are blind!!

yes ,of course. there is a lesson in our textbook that talk about the body language. it said nodding means 'yes',if a chinese act like that.but it is absolutely different if he/she is an indian.

It is fun to read about.