For most infants and children, language develops naturally beginning at birth. To develop language, a child must be able to hear, see, understand, and remember. Children must also have the physical ability to form speech.
Up to 1 out of every 20 children has symptoms of a language disorder. When the cause is unknown, it is called a developmental language disorder.
Problems with receptive language skills usually begin before age 4. Some mixed language disorders are caused by a brain injury, and these are sometimes misdiagnosed as developmental disorders.
Language disorders may occur in children with other developmental problems, autistic spectrum disorders, hearing loss, and learning disabilities. A language disorder may also be caused by damage to the central nervous system, which is called aphasia.
Language disorders are rarely caused by a lack of intelligence.
Language disorders are different than delayed language. With delayed language, the child develops speech and language in the same way as other children, but later. In language disorders, speech and language do not develop normally. The child may have some language skills, but not others. Or, the way in which these skills develop will be different than usual.