Exact causes of speech disorders are not known but some factors are linked with Speech Disorders.
- Hearing loss - Impaired hearing is a very common cause of Speech Disorders.
- Heredity - Family heredity may be responsible for Speech Disorder. Heredity may also determine size of child's mouth, jaw; teeth arrangement; strength of facial muscles which plays a role in proper speech. Also there could be a strong family inheritance in stuttering. This is one of the important causes of speech disorders.
- Neurological Disorder - Progressive neurological disorder can cause speech disorders. Conditions like brain tumour, traumatic brain injury, muscular dystrophy, autism, cerebral palsy, Parkinson's disease and dementia etc may also cause speech disorder.
- Oro facial myo-functional disorders - This disorder causes speech disorder by exaggerated forward movement of tongue during speech or swallowing. This is normal in infancy but improves as we grow up. But if it fails to improve it can lead to speech disorders. This is one of the chief causes of speech disorders.
- Medical Condition- Enlarged adenoids or tonsils can also block the airways leading to forward protrusion of the tongue. Also damage to vocal cord, polyps, nodules, vocal cord paralysis, oral cancer, laryngeal carcinomas may cause Speech Disorders. These are leading causes of speech disorders.
- Brain injury- Stroke can result in apraxia of speech
- Poor intellect- It can also result in speech disorders.
- Physical or structural impairment- Structural impairments like cleft lips, cleft palate, tongue deformities, dental deformities can also cause speech disorders.