Volume 2, Issue 3- April/May 2002

VoiceXML: A Publishing Standard for Accessibility

By Brian Ty Graham

(Continued from Part 1)

Accessibility Through VoiceXML

VDF is a solution to the problems mentioned above. Although accessibility publishing using Braille has a large following, less than 10 percent of the visually impaired actually read Braille. In addition, printing to Braille is expensive for even the simplest types of documents. Other accessibility initiatives such as DAISY (Digital Talking Books) have still not provided a true means of publishing to a readily accessible format. While DAISY provides a simple means of listening to a book via a physical reading device, it does not address the many who want accessibility via a telephone speech interface. Government agencies that support accessibility are still trying to solve the problem of using one format to provide accessibility to all persons.

The advent of VoiceXML overcomes the barriers for providing universal accessibility. The solution to accessibility was hidden within the VoiceXML language itself! The VDF uses advanced techniques in dialog management to grant the maximum control when playing back content via a speech interface. The voice user interface built into each VDF document delivers a complete navigational guide for moving around within any size document as well as for controlling the playback speed and many useful features that mimic the tools usually provided within a graphical user interface.

VoiceXML provides an attractive solution for meeting accessibility requirements described in Section 508 and the American Disabilities Act and here is why:

Universal Accessibility

True accessibility means providing access to all people with disabilities. VoiceXML provides an alternative method for publishing accessible documents by empowering the visually impaired and the disabled as well as the sighted. The versatility of the VoiceXML language also allows users to press touch-tone (or keypad) buttons in place of voice commands in case the user is in a noisy environment or the user cannot speak clearly.

Easy Availability

A publisher can make VDF documents available to any user in numerous ways. Typically, a publisher would use a voice portal (a type of information gateway), which houses the VDF documents in the same manner that a library houses books. Essentially, a voice portal enacts a menu that offers choices of voice applications to the user. Each VDF document is a genuine VoiceXML application that a user can access through a speech interface device such as the telephone. Callers who want to connect to the latest best-seller or product manual for instance would dial a phone number, say the publication they would like to hear, and begin listening and interacting with information.

VDF documents are accessible through a telephony network or on any computing device with speech access via a desktop based VoiceXML interpreter. Publishers can distribute VDF documents in the same manner as any other file format, hence making the documents reusable across any computing platform. The VDF format is very portable. The publisher may choose to distribute the document via email or CD-ROM if providing a telephone number is not an option.

Open Architecture

VoiceXML documents are based on open industry standards, unlike the proprietary and closed IVR platforms. Publishers using VoiceXML as the format for distributing publications may choose the best in class voice browser or platform that suites their users' needs. Unlike other proprietary document formats that limit the user to one vendor, VDF documents can run on all VoiceXML platforms.

Secure Publishing

The telephone provides the ultimate security. Users cannot download voice-enabled publications unless publishers distribute them on external mediums such as CD-ROMs. Since VDF documents are static W3C Compliant VoiceXML files, publishers can reuse their investment in web security using VoiceXML to provide a myriad of standard web based security options.

VoiceXML Document Format

The VoiceXML Document Format makes electronic documents accessible and navigable over any telephone or a speech-enabled computer via a VoiceXML gateway. The power of VDF lies in on-the-fly creation of a navigational guide customized for the document. This navigational guide reads the document's text aloud to the user, starting at the beginning and continuing to the very end. Meanwhile, the user can say voice commands or use the phone dial pad at any time as a media controller to pinpoint a location within the document, change the playback speed, and adjust the volume as the text is read back. For example, users may say commands such as Jump Four Paragraphs, Repeat Sentence, Back Three Sections, Speed Up, Louder and many more. With VDF documents, users can also command the voice browser to spell words, pause and continue, copy and paste text to a clipboard, and even forward the text from the clipboard to a contact via email. A whole library of documents, books, articles, or magazines could very quickly be converted into VDF documents to be accessed by phone or a computing device. All this is at a fraction of the cost of what it will take to produce content in Braille or other formats.

If the user ever gets lost in the VDF document, then s/he can say "Where am I?" and the document will announce the user's location in the document. The user can always receive help if needed simply by saying Help or Tutorial. All of the voice commands are designed using natural speech technology in order to assure the most eloquent and intuitive voice user interface possible using VoiceXML.


The VoiceXML language is a powerful enabler in providing pervasive accessibility solutions, which is one of many attractive reasons for its use as the standard accessibility format. The flexibility of the VoiceXML language, coupled with a simplified deployment alternative such as the telephone, proves that VoiceXML is a clear winner over the Braille and DAISY formats. Speech is the most natural interface known to man. When we are taught other ways to communicate that differ from this natural ability we all share, it becomes increasingly difficult to effectively convey information to all people. The VoiceXML Document Format is a powerful medium that gives the listener complete control in playing back content and manipulating information via a voice only interface. Today, VoiceXML solves the issue of publishing to a standard accessibility format that reaches all types of people, not just the visually impaired. Bundled with other useful voice portal services, the VoiceXML language is very quickly becoming a versatile, readily available, and universally acceptable way to audibly present your most important information and compelling content via simple, natural, and intuitive voice commands.

back to the top


Copyright © 2001-2002 VoiceXML Forum. All rights reserved.
The VoiceXML Forum is a program of the
IEEE Industry Standards and Technology Organization (IEEE-ISTO).