Alzheimer's and Parkinson's disease are often diagnosed late, after the symptoms are well established. (Unsplash) Long before the tell-tale signs of Parkinson’s disease appear, including tremors and muscle stiffness, there are other, more subtle signs of the disease. These include changes in oral pronunciation and language and difficulties breathing or swallowing. People with Alzheimer’s disease can also experience a reduction in their vocabulary and a tendency to repeat certain words. These a