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Speech and Language Impairments


UK [1]

  • around 2.5 million people in the UK have a speech or language difficulty
  • 5% of children enter school with difficulties in speech and language
  • 30% of stroke sufferers have a persisting speech and language disorder

Communication problems may result from:

  • Delayed language development
  • Stammering
  • Inappropriate use of speech sounds
  • Learning difficulties
  • Stroke
  • Head injury
  • Hearing loss
  • Disorders of the voice
  • Cancer of the mouth and throat
  • Degenerative disorders such as Parkinson's disease
  • Cleft palate
  • Physical disabilities
  • Psychiatric disorders

The above information was supplied by the Royal College of Speech and Language Therapists.

Many neurological disorders have the potential to affect speech and language in some way and the range of these disorders is very great.


Language can become disordered when parts of the brain that store words and organise sentences become damaged or disrupted. This disorder is known as aphasia or dysphasia. The types of neurological disorders that cause aphasia are usually ones that occur suddenly, such as stroke or head injury, where some degree of recovery is usual. There are a number of broad types of aphasia.

Speech can become affected when the parts of the nervous system which control the muscles that physically enable us to speak become damaged and can no longer make those muscles work as strongly, quickly and fluently as they need to. This disorder is known as dysarthria.

Difficulty co-ordinating breathing and voice production can occur in many neurological disorders such as after a stroke or head injury and in multiple sclerosis. One or both vocal cords can become paralysed after neurosurgery, a stroke or a head injury. At first it may not be possible to produce any voice at all or the voice may be strained and hoarse. In Parkinson's disease and motor neurone disease on the other hand the voice can be weak and whispery. Neurological diseases can also make control of the pitch and volume very irregular or monotonous.

Some strokes can result in a marked difficulty in directing the lips and tongue in the right way at the right time, despite having normal muscle strength. This makes speech laborious, groping and disjointed and is known as articulatory dyspraxia.

The above information was supplied by the Brain and Spine Foundation.

Further information

Acknowledgements: This section has been developed with the help of the Royal College of Speech and Language Therapists and the Brain and Spine Foundation.

[1] NHS Careers (n.d.) Speech and language therapist. [accessed 26/11/12].


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