Orca is a free and open source, flexible, extensible assistive technology from the GNOME project for people with visual impairments. Using various combinations of speech synthesis and braille, Orca helps provide access to applications and toolkits that support the AT-SPI (e.g., the GNOME desktop, Mozilla Firefox/Thunderbird, OpenOffice/LibreOffice and GTK+, Qt and Java Swing/SWT applications).
The development of Orca has been led by the Accessibility Program Office (APO) of Sun Microsystems, Inc. (now Oracle) with contributions from many community members. The original idea and the first working prototype for Orca were created by Mark Mulcahy, a blind programmer who worked for Sun Microsystems. When Oracle acquired Sun in 2010 they cut developer jobs of full-time developers working on GNOME accessibility components, including its maintainer Willie Walker. Since then Orca is running by volunteers, lead by Joanmarie Diggs.
The name Orca, which is another term for a killer whale, is a nod to the long-standing tradition of naming screen readers after aquatic creatures, including the Assistive Technology product on Windows called JAWS (which stands for Job Access With Speech), the early DOS screen reader called Flipper, and the UK vision impairment company Dolphin Computer Access.
As of GNOME 2.16, Orca is a part of the GNOME platform. As a result, Orca is already provided by default on a number of operating system distributions, including Open Solaris, openSUSE, and Ubuntu.