Parkinson’s Speech Therapy with Houston Area Parkinson’s Society (HAPS.) Join a speech pathologist from our local HAPS every Tuesday from 1-2 PM for speech therapy. Parkinson’s disease affects not only movement but also muscles in the face, mouth and throat that are used to speak. This may cause a person’s voice to change, as well as dysarthria, or difficulty in speaking, and dysphagia, or difficulty in swallowing. Speech may become slurred, mumbled or rapid, and the voice softer. For some, it may be difficult to breathe, find words or participate in fast-paced conversations. These problems may be referred to a speech and language therapist.