Phonological disorder is a failure to use speech sounds appropriate for the individual's age and dialect.

This disorder is more common in boys. Approximately 10% of children under age 8 and 5% of those over age 8 have the disorder. By age 17, only 0.5% are affected.

The cause of phonological disorder in children in unknown. There may be a genetic component since a large proportion of children with this problem have relatives with a type of similar disorder. Other risk factors seem to be low socioeconomic status and coming from a large family.

• failure to produce and use sound appropriately
• substituting one sound for another
• omitting sounds

Certain medical conditions involve phonological disturbances and should be ruled out before a diagnosis of phonological disorder is made. These include hearing impairment, anatomical problems (such as cleft palate), neurological conditions (such as cerebral palsy), and cognitive problems (like mental retardation).

The child should be evaluated for these and other similar conditions. Cultural considerations (such as bilingualism and the child's familial dialect) should also be assessed to ensure proper diagnosis.

Recovery is sometimes spontaneous with milder forms of this disorder. Speech therapy is considered the most successful treatment.

The outcome varies, usually as a function of the age of onset and level of severity.

In severe cases, the child may have problems making basic needs known even to family members. In milder forms, the child may have difficulty being understood by people outside the immediate family. Problems with social interaction and academic performance may occur as a result.

Call your health care provider if your child does not seem to be learning to speak clearly at an appropriate age.