This is not a difficult problem, but a "closed" problem. At least in this circle in China, it has been solved. People who speak normally will imitate stuttering and will also stutter. People who stutter will stutter and will not imitate normal speech. So the key to the problem is not what "stuttering" is, but what normal speech is. The essence of speaking is muscle movement, lung breathing, vocal cord vibration, and mouth and tongue movement. Each syllable corresponds to a muscle movement. If the movement is wrong, then the pronunciation is wrong, and the situation is abnormal pronunciation. Children's pronunciation organs need time to develop and do not support many muscle movement behaviors, so stuttering is prone to occur. When the pronunciation organs mature and can support muscle movement, the pronunciation will return to normal. Because of the problem that is considered, the stuttering problem is deliberately labeled wrong. Depression doctors think stuttering is a depression problem, social doctors think stuttering is a social problem, psychologists think stuttering is a psychological problem, and autism doctors think stuttering is a loneliness problem. They are all actions done for profit.