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Causes of speech problems

Speech is a complicated process. Speaking involves physical actions to produce sound, as well as thoughts and responses from the brain which control these actions and decide what will be said.


Dysarthria is a speech problem that occurs when MS damage in different parts of the brain affects the way speech is produced.

For example:

  • damage in one part of the brain might affect the muscles of the tongue and lips, making it difficult to pronounce precise sounds
  • damage in another area might weaken the diaphragm, affecting breath control and volume.

The connections between the brain and the spinal cord – the area known as the ‘brainstem’ – are particularly important for controlling speech. If these are damaged due to MS, speech problems are more likely to occur.

Some of the more common changes in speech due to dysarthria in MS are:

  • slurred, imprecise or slower speech
  • low volume or weak voice
  • difficulty with resonance and pitch control
  • sounding like you're speaking through the nose
  • long pauses between words, or between syllables


Dysphasia is rare, and can make it hard to understand what is being said (‘receptive dysphasia’), or difficult to recall vocabulary or find the right way to say something (‘expressive dysphasia’).

MS can also cause other changes in memory and thinking that might affect how someone speaks, known as cognitive difficulties.


Some drug treatments, including those used to treat bladder problems, can cause a dry mouth as a side effect, making speaking more difficult. If this is an issue for you, bring it up with your doctor, who may be able to adjust your medication to lessen this side effect.