Accessibility-HOWTO(1).pdf

Linux Accessibility HOWTO

Michael De La Rue

Sharon Snider

v3.1, June 21, 2002

Revision History

Revision v3.1

2002−06−21

Revised by: sds

Updated and converted to DocBook XML.

Revision v3.0

2001−10−25

Revised by: sds

Updated and converted to DocBook SGML.

Revision v2.11

1997−03−28

Revised by: mdlr

Last Linuxdoc revision.

The Linux Accessibility HOWTO covers the use of adaptive technologies that are available for the Linux

operating system, as well as the software applications and hardware devices that can be installed to make

Linux accessible to users with disabilities. The information provided targets specific groups of individuals

with similar disabilities.

Linux Accessibility HOWTO

Table of Contents

1. Introduction. ....................................................................................................................................................1

1.1. Distribution Policy. ...........................................................................................................................1

2. The Linux Operating System. ........................................................................................................................2

2.1. Assistive Technologies Available for Linux.. ...................................................................................2

2.2. Usability. ...........................................................................................................................................2

3. Visual Impairments. .......................................................................................................................................3

3.1. Technologies for the Visually Impaired. ..........................................................................................3

3.1.1. Screen Readers. .................................................................................................................3

3.1.2. Speech Synthesizers.. ........................................................................................................3

3.1.3. Screen Magnifiers. ............................................................................................................4

3.1.4. Adjusting the Screen's Resolution. ...................................................................................5

3.1.5. Braille Devices. .................................................................................................................5

3.1.6. Cursors for X Windows. ...................................................................................................6

3.1.7. Audio. ...............................................................................................................................6

3.1.8. Additional Resources. .......................................................................................................7

4. Hearing Impaired. ...........................................................................................................................................8

4.1. Assistive Technologies for the Hearing Impaired. ...........................................................................8

4.1.1. Telecommunications Devices for the Deaf (TDD). ..........................................................8

4.1.2. Closed Captioning.. ...........................................................................................................8

5. Physically Disabled .........................................................................................................................................9

5.1. Keyboard Navigation. .......................................................................................................................9

5.2. Assistive Technologies for the Physically Disabled. ........................................................................9

5.2.1. On−Screen Keyboard. .......................................................................................................9

5.2.2. Speech Recognition. .......................................................................................................10

5.3. Additional Resources. .....................................................................................................................10

6. Cognitive, Language, and Other Impairments. .........................................................................................11

6.1. Assistive Technologies for Cognitive, Language and Other Impairments. ....................................11

6.1.1. Screen Readers and Speech Synthesis. ...........................................................................11

6.1.2. Keyboard filters and Word Processing. ..........................................................................11

6.1.3. Speech Recognition. .......................................................................................................11

7. Developing Accessible Applications. ...........................................................................................................13

8. Other Helpful Information.. .........................................................................................................................14

9. Acknowledgments. ........................................................................................................................................15

1. Introduction

The purpose of this HOWTO is to introduce the tools, applications, and configuration utilities that are

available to Linux users who are disabled. The information provided targets groups of individuals with the

following disabilities:

· Hearing Impaired

Visually Impaired

· Physically Disabled

· Cognitive, Language, and Other Impairments

Please send any comments, or contributions via e−mail to Sharon Snider. This document will be updated

regularly with new contributions and suggestions.

1.1. Distribution Policy

The Access−HOWTO may be distributed, at your choice, under either the terms of the GNU Public License

version 2 or later or the standard Linux Documentation Project (LDP) terms. These licenses should be

available from the LDP Web site: http://www.linuxdoc.org/docs.html . Please note that since the LDP terms

do not allow modification (other than translation), modified versions can be assumed to be distributed under

the GPL.

ViaVoice® is a registered trademark of International Business Machines Corporation.

1. Introduction

2. The Linux Operating System

The Linux operating system has many software applications and utilities that run in the non−graphical

environment. The graphical user interface (GUI), which is often referred to as X Windows, is clearly separate

from the underlying non−graphical, text−only environment. One major reason that a visually impaired

individual can use Linux is that network connectivity is built in to the operating system and provides full

access to the Internet from the non−graphical interface. All visible text on the screen can be translated using a

screen reader and speech synthesizer.

Over the past few years many improvements have been made to the GUI, and many of the desktops now

provide features and enhancements designed for accessibility. In the following sections you will find

information on the tools, utilities, and applications that are available to assist users in configuring their

desktop environment.

2.1. Assistive Technologies Available for Linux

Assistive technologies are computer hardware devices and software applications that provide individuals with

impairments access to the information and applications on a computer. Although there are not many

commercial applications available specifically for Linux accessibility, there are free software applications

that can make the computer more accessible. Detailed information on assistive technologies that are available

has been listed in this document based on the type of disability.

2.2. Usability

Linux has the advantage over Windows that a large majority of Linux software has been developed for the

console. Although many programs are now being developed for the GUI, programs continue to be written for

the non−graphical, text−based environment. Linux originated as a programmer's operating system and, for

the physically disabled, this means that it is easy to build and customize programs to suit an individual's

needs.

The windowing system used by Linux (X11) includes many programming tools that enable further

modification and customization of the GUI. KDE and GNOME have included many accessibility and

usability features in their latest releases and are continuing to test, upgrade, and enhance the graphical

environment. The following are links to KDE and GNOME's accessibility and usability projects:

· GNOME Accessibility Project − http://developer.gnome.org/projects/gap/ .

KDE Accessibility Project − http://accessibility.kde.org/ .

· KDE Usability Project − http://usability.kde.org/ .

· GNOME Usability Project − http://developer.gnome.org/projects/gup/ .

2. The Linux Operating System

3. Visual Impairments

There are two categories of visual impairments. Individuals who are partially sighted (for example, blurred

vision, near and far−sightedness, color blindness) and those who are totally blind. Assistive technologies are

available for the Linux operating system for visually impaired users, and many of the software packages are

free.

3.1. Technologies for the Visually Impaired

The following is a list of assistive technologies for visually impaired users:

3.1.1. Screen Readers

Screen readers are software applications that are installed on the computer to provide translation of the

information on the computer screen to an audio output format. The translation is passed to the speech

synthesizer and the words are spoken out loud. Currently, fully functional screen readers are only available

for Linux in console mode. This section describes some of the most common screen readers.

Emacspeak is the complete Audio Desktop is an excellent non−graphical, text based interface for

users who are visually impaired. This application can be used as a screen reader in conjunction with a

hardware synthesizer or IBM ViaVoice® Run−time text−to−speech application. More information

and software packages of are available at: http://www.cs.cornell.edu/home/raman/emacspeak/ . The

Emacspeak HOWTO http://www.ibiblio.org/pub/Linux/docs/HOWTO/ includes a tutorial and

installation guide.

Jupiter Speech System is a screen reader for Linux in console mode. A user guide and software

packages are available at: http://www.eklhad.net/linux/jupiter/ .

Screader is a screen reader for Linux in console mode that works with the Festival software speech

synthesizer and the Accent hardware synthesizer. Information and downloads are available at:

http://www.euronet.nl/~acj/eng−screader.html .

Speaker is a new plugin for the Konqueror file manager and Web browser. Speaker provides Text to

Speech using the Festival speech system or IBM ViaVoice. Downloads are available at:

http://dogma.freebsd−uk.eu.org/~grrussel/speaker.html .

Speakup is a screen review package for the Linux operating system. It requires a hardware speech

synthesizer, such as the DecTalk Express. An installation boot disk and packages are available at:

http://www.linux−speakup.org/ that allow a visually impaired user to install the Linux operating

system.

ZipSpeak is a talking mini−distribution of Linux. More information and software packages are

available at: http://www.linux−speakup.org/zipspeak.html .

3.1.2. Speech Synthesizers

Speech synthesizers can be a hardware device or a text to speech (TTS) software application that creates the

sounds necessary to provide speech output. Hardware synthesizers are available for the Linux operating

system; however, they can be very expensive and must be compatible with the screen reader application in

order to function properly. The alternative is to download and install a software synthesizer such as IBM's

3. Visual Impairments

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