Dysarthria is a motor speech disorder that affects the ability to articulate sounds and words due to weakness, paralysis, or incoordination of the muscles used for speech. This can result in slurred speech, slow speech, distorted speech, or difficulty speaking loudly or clearly. Dysarthria can be caused by a variety of conditions, such as stroke, traumatic brain injury, Parkinson's disease, multiple sclerosis, or cerebral palsy.