The demo excels at . You can tell the voice to be happy, sad, or whispering. It turns the monotone "I am happy to see you" into something that actually sounds... well, happy.
Instructional designers use the demo to test pronunciation of industry jargon. For example, a medical school tests "Cyanocobalamin" (Vitamin B12) across ten voices to see which enunciates clearly without sounding sterile. acapela text to speech demo