Screen reader

Screen readers are software applications that attempt to convey what is seen on a screen display in a non-visual way, usually as text to speech, but also into braille or sound icons. Screen readers are essential to people who are visually impaired, illiterate, or have a learning disability. There are some browser extension screen readers, but most screen readers operate system-wide for all user applications, not just the browser.

In terms of web accessibility, most user agents provide an accessibility object model and screen readers interact with dedicated accessibility APIs, using various operating system features and employing hooking techniques.