VoiceXML
An XML-based standard for speech-enabled applications. It defines how a dialog is constructed and executed between a caller and a computer running speech recognition and/or text-to-speech software.
VoiceXML incorporates the flexibility to create speech-enabled Web-based content or to build telephony-based speech recognition call center applications.
Specifically, VoiceXML outlines a common language to follow when programming a speech application. In VoiceXML, many of these rules are referred to as tags, as used in HTML. Tags denote actions for creating dialog between a human voice and speech recognition system.
An example of a VoiceXML tag would be to queue an audio output. Main components of a VoiceXML-based service include tags, forms and rules that define the content, and a speech browser for interpreting and presenting audio content.
Vocabularies and grammars are the key components that define the input to a speech-enabled page. The vocabulary consists of the words to be recognized by the speech recognition engine. For example, a vocabulary for a flight information system might consist of city names and travel-related words such as "leaving" and "fly." Grammars provide the structure to identify meaningful phrases. A vocabulary and grammar are combined within a speech-enabled application to define speech recognition within a reasonable range of efficiency for both the caller and the speech recognition processor.
Designing a speech application includes presenting data for delivery over the phone, constructing a call flow and enabling prompts and grammars. VoiceXML provides a common set of rules as a flexible foundation, but it's up to the designer to create the appropriate flow and personality for a speech system.
Just as HTML content is interpreted by a browser and presented visually over the Web, so must VoiceXML be understood or interpreted for presentation over the telephone by a speech, or voice, browser. The speech browser serves as a gateway between a call and an Internet connection. It interprets VoiceXML code and manages dialog between callers and VoiceXML content located at a Web site.
Speech browser software also maintains the calls, presents voice prompts that equate to URLs and downloads pages for audio interaction.
From XML gives voice to new speech apps, Network World Tech Updates, 07/30/01.
Also see SALT
Additional resources
VoiceXML Forum
Industry group establishing the standard.
Latest VoiceXML news and analysis from Network World Fusion
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