Babies who do not speak at 20 months may be due to genetic factors, but may also be related to the language environment, hearing abnormalities, or autism. Parents should not only communicate with their babies more and encourage them to talk, but also take them to the doctor in time for examination and rehabilitation treatment for the cause. Common causes 1, genetic factors: parents speak earlier when they are young, the baby will also speak earlier. Some parents speak later as a child, the baby may also speak late; 2, language environment: if the language environment provided to the baby is too monotonous or complex, parents usually communicate with the baby less, did not create a good language environment, it may lead to the baby 20 months still can not speak; 3, hearing abnormalities: baby if there are symptoms of hearing abnormalities, easily lead to delayed language development, open speech time late, or even For example, if the baby has a serious hearing loss, deafness symptoms, due to the inability to hear outside sounds, will also lead to the phenomenon of non-speaking; 4, autism: baby due to brain development, congenital genetics and other factors leading to autism, will cause the phenomenon of non-speaking or communication disorders. Solution 1. Parents should be more patient, encourage their babies to speak, train them to use language to express their needs, and pay attention to creating a good language environment; 2. Parents of babies with autism should take their babies to professional rehabilitation training institutions for treatment in a timely manner, and also create a good relationship with their children in daily life under the guidance of rehabilitation doctors, and take the initiative to guide their children to speak in order to increase 3. For babies with hearing impairment, parents should promptly bring them to the hospital for hearing tests and, if necessary, to wear hearing aids to help them recover their hearing. Attention usually baby in 12 months can make meaningful syllables, 18 months can reach the period of vocabulary explosion growth, if 20 months can not speak, even can not make meaningful sounds, must be as soon as possible to seek medical advice to clarify the cause.