1 year 9 months can not speak, may be normal, may also be suffering from disease (hearing impairment, etc.) caused by. 1. If the child is 1 year and 9 months old with normal hearing, normal development of articulation organs and mental development, it may be normal. The child’s inability to speak may be caused by insufficient training in normal times, family heredity and other factors, and most of the child can speak normally after strengthening language training as the child grows older. 2. If the child has a hearing impairment, can not pronounce normally, or the child is accompanied by intellectual development backwardness, mental retardation phenomenon, is an abnormal phenomenon, considering the disease factors, such as congenital deafness, cerebral palsy, brain dysplasia and so on. 1 year 9 months can not speak, there may be other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.