Mouth is the main channel for everyone to express their thoughts and release their emotions. Words come from the mouth, and at any time, communication between people is inseparable. Mouth movements are rich and varied. From the linguistic point of view, every action is closely related to the speaker's psychological activities and always reflects the psychology and emotions of the parties. Therefore, in the process of communicating with the other party, we should not only listen to what the other party is saying, but also pay attention to the change of the other party's mouth shape, so as to find out the real thoughts of the other party. For example, the inverted "U" shape of the mouth indicates that a person is full of sadness. When a person's heart is full of sadness or is troubled by countless negative emotions, his mouth will droop downward, forming an inverted "U" shape. The word "χ" means that when a person is surprised or happy about something or someone, he will open his mouth. When a person is in a state of tension and depression, the muscles of the mouth will become tense, and the lips will become tight and flat. With the increasing tension, the mouth shape will gradually "contract". This expression is very common in life. For example, when a teacher talks with a student, the teacher states his own views first, and then asks the students for their opinions.

Students often nod their heads to divert their attention, or squint at the ground without talking. These are all manifestations of his inner disapproval. Students may be thinking that after the conversation, he will still follow his own ideas and will never change. Therefore, when we try to convince others, if we find that the other party has these little moves, we should adjust our strategies in time and guide him/her from another angle. Or you can give up persuading the other party for a while, stop wasting your time and energy, and then look for the next opportunity to win the other party's approval. There are still many micro-expressions in the human body. If we want to make full use of body language as a communication tool, we must conduct in-depth research on it. In this regard, we should start from the basis of body language.