The cause of many communication disorders is unknown.

In some cases, heredity appears to play a role. For example, as many as 60 percent of people who stutter have a family member who also stutters, according to the Stuttering Foundation of America. Research also indicates that there is a link between stuttering and and inability to control emotions and attention in children. Certain developmental disorders (e.g., autism) can also cause communication disorders.

In other cases, an illness, accident or injury to the brain or another body structure may trigger a communication disorder (e.g., aphasia, apraxia of speech). Anatomical conditions such as a cleft lip or palate (a birth defect characterized by a split in the lip or roof of the mouth), and cognitive problems such as mental retardation may also contribute to communication disorders. Malnutrition and vitamin deficiencies may also be a factor.

Communication disorders are typically diagnosed during childhood. In addition, those disorders identified by the American Psychiatric Association appear to be more common in males than in females. This includes expressive language disorder, mixed receptive-expressive language disorder, phonological disorder and stuttering.