Parkinson's disease can affect the muscles of the lips, tongue, throat, voice box (larynx), and lungs, all of which are involved in producing speech. Stiff, slow muscles in these areas may lead to:

• Low voice volume or soft speech.
• Imprecise speech sounds.
• Speaking too fast or too slow.
• Monotonous voice.
• Hoarseness.

A speech therapist (also called a speech-language pathologist) can help you learn ways to improve your speech. He or she may provide:

• Breathing exercises to improve voice volume.
• Speech exercises to make your sounds clear and precise.
• Tips to help make your speech rate more regular.
• Exercises to practice pitch changes when you speak.