Definition of a Screen Reader: A screen reader is a software application that attempts to identify and interpret what is being displayed on the screen.
A Screen Reader is for the blind and what it does is read text on a computer using a computer sound card. Three examples of a screen reader are Emacspeak, Spoken web, NVDA. I would prefer blind people to buy NVDA because it has more to than the others and its free. you can order a screen reader online. Usually screen readers cost from 790-890