Orca is a free, open source, flexible, and extensible screen reader
that provides access to the graphical desktop via user-customizable
combinations of speech and/or braille.

Orca works with applications and toolkits that support the assistive
technology service provider interface (AT-SPI), which is the primary
assistive technology infrastructure for the Solaris and Linux
operating environments.  Applications and toolkits supporting the
AT-SPI include the GNOME GTK+ toolkit, the Java platform's Swing
toolkit, OpenOffice/LibreOffice, Gecko, and WebKitGtk.  AT-SPI support
for the KDE Qt toolkit is currently being pursued.

See also http://wiki.gnome.org/Projects/Orca for detailed information
on Orca, including how to run Orca, how to communicate with the Orca 
user community, and where to log bugs and feature requests.

brltty and liblouis are optional dependencies for braille support.