Some children who used to speak well, but from a certain period of time, refuse to speak, are called mutes, often from 3-5 years old, but also in school-aged children. Many reticent children exhibit a refusal to speak, silence, or whisper in some situations, while being able to communicate normally verbally in others, a phenomenon known as selective reticence. When a child is silent, he or she may use body language such as gestures, nodding, shaking hands, and sometimes writing to communicate. The refusal to speak is usually in the context of school or in the presence of strangers; a few do the opposite, speaking at school but not at home, or they may refuse to speak with adults but speak with children or acquaintances. The cause of these children’s reticence is not due to a physical illness, but is related to personality, family environment, psychological factors, and developmental factors. These children are more sensitive, timid, withdrawn, vulnerable, and dependent, and their parents are often overly dominant or protective of the child, or the parents themselves have character defects. Some children have a bad parental relationship, divorced parents, and have been psychologically stimulated at home or on certain occasions. Some children show some developmental immaturity, such as starting to speak at a later age, having functional enuresis and feces loss, and showing immaturity in the EEG. These factors cause children to also often show some difficulties in interacting with people on a regular basis, for example, they do not know how they should interact with people, especially unfamiliar adults, and appear shy, withdrawn, and easily upset in their interactions with people. Parents should not force their children to talk or tease them, such as “Say something”, “You’re dumb”, or “This child just doesn’t talk to people, he’s useless! Do not damage the child’s self-esteem in front of outsiders. Since most of this phenomenon is psychogenic, it is necessary to understand the reasons for the child’s reticence, improve and eliminate the unfavorable factors, and then create a relaxed atmosphere to induce the child to speak, whether the child speaks or not parents should kindly speak to him more; for younger children this can be done in a game. When the reticent child gains a sense of security and confidence, he or she will speak. Get help from a psychologist if necessary. Muteness can also be a symptom of other mental disorders, such as depressive muteness, dysthymic muteness, muteness in schizophrenia, and muteness in autism, so the diagnosis of selective muteness requires a detailed psychiatric-psychological examination for differential diagnosis to exclude muteness in depression, dysthymia, major psychiatric disorders, and autism. Only in a very small number of children, muteness is not related to psychological and environmental factors, then the possibility of neurological brain disorders should be examined.