Language is used by people for sending messages to one another. It is very useful because it can help you make yourself easily understood. When you are talking with others,you are not just using words, but also using expressions and gestures. For example, waving one‘s hand is to say "Good-bye." A smile and handshake show welcome, and clapping hands means congratulations. Nodding the head means agreement, but shaking the head means disagreement. The gestures are accepted both by Chinese and foreigners as having the same meanings.