Have certain words practiced and available to speak to make the mouth muscles work.
Memorize poems or famous sayings to practice each day -- keep the brain-mouth connection strong.
Train your posture to maintain an upright stance or seated position.
Train your voice to be loud, with slow, clear speech patterns.
Train your eyes to look others in the eye, and blink occasionally.
Train your listening skills to pay attention to what you hear.
Train My Brain?
Get up often and stretch to maintain joint full extension in fingers, arms, and legs.
Move to increase or maintain your motivation
Varanese, S., Perfetti, B., Ghilardi, M.F., and Di Rocco, A. (2011).
Apathy, but Not Depression, Reflects Inefficient Cognitive Strategies in Parkinson's Disease.