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 3% of preschool children and 2% of children aged 6-7 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 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. These should be ruled out before a diagnosis of phonological disorder is made. Such disorders 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 considered, to ensure correct diagnosis.

Milder forms of this disorder may disappear on their own. Speech therapy is considered the most successful treatment.

The outcome depends on the age at which the disorder started, and on how severe it is.

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.