Final answer:
Dysarthria is characterized by slurred speech due to impaired movement of muscles used in speech production, and it's not typically associated with flat affect, stuttering, or joint pain.
Step-by-step explanation:
A patient with dysarthria is most likely to exhibit slurred speech. Dysarthria is a motor speech disorder which results from impaired movement of the muscles used for speech production, such as the tongue, lips, vocal folds, and/or diaphragm. It does not commonly involve flat affect, severe stuttering, or painful joints, which are symptoms associated with other conditions. Slurred speech can be a result of neurological disorders, such as Parkinson's disease for instance, that include slowed movements and speech changes, or other medical conditions affecting brain function and muscle control.