It is not normal for a one year and eight months old child not to speak. It may be caused by less communication between the parents and the baby, neurological diseases, autism, hearing abnormalities, etc. It is recommended to go to the hospital in time to find out the cause of the disease. 1. Parents and babies communicate less: because parents usually communicate less with the baby, so the baby will not speak. 2. Neurological diseases: If the inability to speak is accompanied by abnormal actions, it may be a neurological disease or a genetic metabolic disease, which should be promptly treated in the hospital. 3. Autism: If the baby does not speak and at the same time does not play with other babies, has very little attachment to the parents and seldom communicates with others, he or she may be autistic and should go to the hospital in time for evaluation. 4. Hearing abnormality: If the baby’s response to sound is very weak, there may be hearing abnormality, need to go to the ear, nose and throat department for examination. If your baby is one year and eight months old and can’t speak, parents should seek timely medical attention and actively cooperate with the doctor to identify the cause of the disease, so as to avoid delaying the condition or triggering adverse reactions.