Corporal Language (also know as Kinesics or quinésica) is everything you transmit through your body, gestures or facial expressions. These sometimes can tell your feelings, the perception of the person you are talking to or the person you are talking about they can also tell your mood.
Most people would love to be able to read other people thoughts, well Body language or Corporal Language can betray your feelings fully or perception of the person you are interacting.
Body movements sometimes bring special meaning to the spoken word, during a speech or communicative event, these can have a meaning or reflect an intention, sometimes unwanted. These movements are studied by kinesics or quinésica.

Gestures most of the time are the key to know what someone is thinking bout you or what you've just said, gestures reflect wether if a person is comfortable, uncomfortable, if the person is telling the truth, if the person feels awkward, there are several ways to notice what someone is thinking.

A gesture is a form of nonverbal communication executed with a body part, and produced by the movement of joints and muscles of the arms, hands and head or face expressions.
Posture:
Some times the posture of a person can tell allot, for example in a Job interview if you have your arms crossed it sometimes means that you are not fully comfortable and that you are not answering 100% with the True, moving your feet and your hands tells that you are impatient or uncomfortable, most interviewers besides of interviewing you, they read your body language while you are answering a question, perhaps you'll not notice this but this is very important on a Job interview.
Facial Expressions: Facial Expression reflect your mood and emotions, these are often used to emphasize something. When we someone smiling we think he's happy or enjoying something however smiling can be used to hide our true feelings or opinions, smiling is often used as a mask.
Some other Gestures that might betray you:
*Watching your Clock while talking to someone tells that you are in a hurry or just uncomfortable.

*Biting your nails shows insecurity.
*Crossing your arms shows a defensive attitude.
*Having your hands on your checks shows "evaluation".