Assistive technologies
      target narrowly defined populations of users with specific disabilities. The assistance
      provided by an assistive technology is more specific and appropriate to the needs
      of its target users. The mainstream user agent may provide important functionality
      to assistive technologies like retrieving Web content from program objects or parsing
      markup into identifiable bundles. Example Assistive technologies that are important in the context of this document include
      the following: screen magnifiers, and other visual reading assistants, which are used by people with
         visual, perceptual and physical print disabilities to change text font, size, spacing,
         color, synchronization with speech, etc. in order to improve the visual readability
         of rendered text and images; screen readers, which are used by people who are blind to read textual information
         through synthesized speech or braille; text-to-speech software, which is used by some people with cognitive, language, and
         learning disabilities to convert text into synthetic speech; speech recognition software, which may be used by people who have some physical disabilities; alternative keyboards, which are used by people with certain physical disabilities
         to simulate the keyboard (including alternate keyboards that use head pointers, single
         switches, sip/puff and other special input devices.); alternative pointing devices, which are used by people with certain physical disabilities
         to simulate mouse pointing and button activations.