When a 3-year-old baby appears to be non-verbal and he understands all adult speech, i.e., he can understand adult speech, it needs to be determined whether the baby has been non-verbal or rarely speaks. Have a systematic examination, such as oral examination, neurological examination, EEG, etc., done as soon as possible. Determine if the occurrence is related to the language environment or if it is caused by stress, autism, etc. Once found should immediately seek medical attention, early screening, diagnosis, and timely intervention measures. 1, language environment: 3-year-old babies lack the environment with which they can communicate, communication, failure to learn to speak at the stage of language exercise, it may appear that they can not speak, but can understand the phenomenon of adult speech, parents should actively guide, more talk to the baby, more take the baby to play with peers, communication, etc., to exercise the baby’s language Organizational ability, after long-term persistence can help it return to normal; 2, stress reaction: 3-year-old baby suffered a large fright and other factors can lead to the emergence of stress reaction, manifested as no impact on the ability to understand, but has not been talking, that is, the phenomenon of not talking, but can understand adult speech. Should be promptly to the hospital, active psychological intervention, through the doctor, parents, teachers and other cooperation, to help the baby out of the stress state; 3, autism: this condition of 3-year-old baby not only can not speak and other language development disorders, but also may have a narrow range of interests, eccentricity, stereotypical behavior and other symptoms. It should be diagnosed and intervened as early as possible, through behavior therapy, family therapy, special education and other interventions, and at the same time under the guidance of doctors to carry out sensory and auditory training to promote its recovery; 4, other causes: such as the existence of abnormalities in brain development, language development, etc., can also lead to 3-year-old baby can not speak, can understand adult speech, need to carry out rehabilitation training as early as possible, such as through the way to do games to make the baby learn Words, symbols, etc., and give positive encouragement at the right time, such as applause, rewards, etc., to exercise the baby’s ability to speak, think, etc. In addition, parents should pay enough attention to their 3-year-olds to avoid delaying treatment due to parental neglect. They should also communicate effectively and positively with their babies and shape a warm and happy family atmosphere so that the family, parents, etc. do not cause harm to their babies.