Speech disorders

Defects or disturbances in speech that lead to an inability to communicate effectively. Damage to the language centres of the brain (usually due to a stroke, head injury, or brain tumour) leads to aphasia, which may impair speech. Disorders of articulation may be caused by damage to nerves that go to muscles in the larynx, mouth or lips, due to stroke, head injury, multiple sclerosis, or Parkinson’s disease. A structural abnormality of the mouth, such as a cleft lip and palate, can also be a cause. Disorders of voice production include hoarseness and inappropriate pitch or loudness. In many cases, the cause is a disorder affecting closure of the vocal cords (see larynx, disorders of). A voice that is too high or low or too loud or soft may be caused by a hormonal or psychiatric disturbance or by hearing loss. Disorders of fluency include stuttering, which is marked by hesitant speech and repetition of sounds. Delayed speech development in a child may be due to hearing loss (see deafness), slow maturation of the nervous system, poor tongue and lip control, lack of stimulation, or emotional disturbance (see developmental delay). Many people with speech disorders can be helped by speech therapy.