Screen readers are programs primarily designed for blind people. Their function, therefore, is to access and read information from the screen. Over the years, screen readers have undergone major improvements and have been adjusted to the graphical interface of the Windows operating system. They not only read information written in a document that contains simple text, but also read tables, spreadsheets, and emails. In fact, the most commonly used Microsoft applications – Word, Excel, PowerPoint, Access, and Outlook – are easily accessible with screen readers. Screen reader users can now perform most of the functions as quickly as people who do not use screen readers.
For screen readers, the foreground and the background colors of a document do not matter. The program will read large white letters on a black background with the same speed and accuracy as small dark blue letters on a black background. It can even read black letters on a black background, since it does not rely on the information that the sighted people see on the screen, but rather on the information that is provided internally by the software. However, screen readers can read text attributes, such as font style, font size, and font color. It is not necessary to avoid these attributes when a document is given to a screen reader user.
Screen readers come with a variety of voices from which to choose. They can be adjusted to read at a particular speed or to read with a certain pitch or inflection. At one time they read through an external speech synthesizer, now largely replaced and updated by software speech synthesizers which work with a soundcard and a pair of headphones or speakers. The transition from the external speech synthesizer to the sound card has been a significant advancement – one that has helped minimize the gap between blind and sighted computer users. While in the past a screen reader user had had to ensure that any computer he intended to use had an external speech synthesizer, it is now possible for him to use almost any computer at any workplace or educational institution, since most computers are equipped with a soundcard. Many also include a set of speakers. Users can carry a pair of headphones from station to station, in case no speakers are available or in case they work with people who require a quiet working environment and do not wish to be disturbed by a voice coming from speakers.
currently most popular screen readers are jaws for Windows, Windows Eyes and Hal.