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LinuxScreenAccess

Blind and visually impaired users have several screen access solutions within Linux. Each solution has multiple parts to set up.

GUI access

Orca

Working in the graphical user interface, Orca, which is part of the Gnome desktop environment is the most developed. Orca is included with Ubuntu and is better configured under the Vinux distribution. Orca can be slow and unstable and doesn't work with all graphical packages. However Orca supports Braille, and speech in a coordinated form. !!Console-based access

Yasr

In console- text-based Linux, the Yasr screen reader is a package that is available for most distributions. Yasr stands for Yet Another Screen Reader. Yasr is small, fairly easy to set up and not difficult to learn.

Speakup

However most console users prefer Speakup, a kernel patch that gives access to Linux from boot-up to shut-down as it is embedded directly in to the kernel so it is effectively part of the operating system. Note that Speakup is provided in the staging part of the kernel so can bel oaded with one command.

Fenrir

Fenrir is a Python absed screen reader developed in Germanny that supports Linux, BSD and all of the commonly used synthisizers, it has up to date development and a friendly community.

Emacspeak

Another solution is emacspeak, which is not a screen reader, but rather a talking desktop. The Emacs editor has long been used as a full desktop replacement especially for programmers, who often do all their Linux-related work from within Emacs. Emacspeak is an add-on that "speech-enables" most emacs functions. A synthesizer that is supported in Emacspeak must have an Emacspeak speech server written for it as Emacspeak doesn't communicate directly with the synthesizer. Yasr also depends on accessing an emacspeak speech server.

Speech synthesisers for Linux

In Linux, a speech synthesizer is programatically independent from the screen reading solution, though it is often installed when the screen reader package is installed.

espeak

The most popular synthesizer is espeak because it is small, fast and portable. Espeak is the same synthesizer used by the Windows open-source screen reader, Nvda.

frestival

A larger, but still portable package is Festival which is a complete speech synthesis system. Several front-ends for Festival exist, including Mbrola which provides, what many believe to be better voices.

Flite

The Flite package is a small Festival run-time that is also sometimes used with Speakup, Orca and emacsSpeak. The eflite package is an emacspeak speech server for flite.

Commercial voices

Commercially the Cepstral and Fonix dectalk are voices whose licenses can be purchased. It is also possible to purchase eloquence, as the viavoice libraries in a package called Voxin through the Oralux foundation. Voxin also can now support some of the popular Vocaliser voices.

Speech adapters

Because Speakup was originally designed for hardware synthesizers, suchas the Apolllo, Accent, Braill 'N' Speak or Dectalk, several "adapters" have been written to make it work with software speech.

Speech Dispatcher is an ambitious project which aims to provide a common framework for all synthesizers to communicate with all screen readers. It can provide speech to Orca if Orca is configured to use it. It also can provide access to Speakup through its speechd-up daemon. Speech-dispatcher is neither a screen reader nor a synthesizer: it is simply a library which standardizes the communication between both entities.

Espeak is another connector, written specifically to connect speakup to espeak.

Debian and Ubuntu users wishing to use eloquence with speakup typically purchase Voxin from Oralux and then configure speech-dispatcher to support it through speechd-up. RedHat and Fedora users purchase a similar license using a package called Ttsynth. Both Voxin and Ttsynth include the viavoice libraries and various connectors to adapt them for speakup, yasr, emacspeak and orca. But Voxin is for Ubuntu and Ttsynth is for Redhat.

The complexity of getting the synthesizer , screen access and the necessary adapters and connectors all installed and configured can be daunting. Unlike Windows, Linux programs are developed world-wide by a volunteer community who do not always coordinate their efforts. Though it is possible to get it all working quite well, many blind and visually impaired user simply choose to access Linux through a terminal using ssh or a serial port.

The advantage of using a screen access solution is that you can interact with Linux directly on the hardware console -- using the machine's actual keyboard and screen. The advantage of not using a screen access solution is that you don't have to figure out how to get it all working.

Brltty

For Braille displays, Brltty is the solution. It supports most displays available either through bluetooth, USB or serial ports. Brltty has limited speech output through Festival.

Brltty is configured using one file, and Braille display support is built-in. brltty does not conflict with screen readers, so it can easily be used together with speech.