SEMINAR ON

“VOICE XML” 

B.NAVYA (12M61D5805)M.TECH I-I Sem

INTRODUCTION

VoiceXML is a language for creating voice-user interfaces,

particularly for the telephone.

It uses speech recognition and touchtone (DTMF keypad) for input,

and pre-recorded audio and text-to-speech synthesis (TTS) for

output.

DTMF

TTS

VoiceXML, speech recognition application development

is greatly simplified by using familiar web infrastructure,

including tools and Web servers.

VoiceXML "interpreter" (also known as a "browser")

running on a telephony server.

VoiceXML can be used for voice-enabled Web

applications.

USE OF VOICE XML

1. As a way to voice-enable a Web site.

2. As an open-architecture solution for building next-

generation interactive voice response telephone

services.

APPLICATIONS

One popular type of application is the voice

portal(speech recognition-based telephone services).

Other application areas, including voice-enabled

intranets and contact centers, notification services, and

innovative telephony services, can all be built with

VoiceXML.

VoiceXML and the voice-enabled Web allow for a new

business model for telephony applications known as the

Voice Service Provider.

This permits developers to build phone services without

having to buy or run equipment.

VoiceXML has its roots in a research project called Phone Web at

AT&T Bell Laboratories.

VoiceXML’s main goal is to bring the full power of web development

and content delivery to voice response applications, and to free the

authors of such applications from low-level programming and

resource management.

GOALS OF VOICEXML

VoiceXML is a markup language that:

• Minimizes client/server interactions by specifying multiple interactions

per document.

• Separates user interaction code (in VoiceXML) from service logic

(CGI scripts).

• VoiceXML is a common language for content providers, tool

providers, and platform providers.

• Is easy to use for simple interactions, and yet provides language

features to support complex dialogs.

SCOPE OF VOICEXML

The language describes the human-machine interaction provided by voice

response systems, which includes:

• Output of synthesized speech (text-to-speech).

• Output of audio files.

• Recognition of spoken input.

• Recognition of DTMF input.

• Recording of spoken input.

• Telephony features such as call transfer and disconnect.

CREATING A BASIC VOICE XML DOCUMENT

VoiceXML syntax involves enclosing instructions (items) within a tag structure in the

following manner:

< element_name attribute_name="attribute_value">

......contained items......

< /element_name>

< ?xml version="1.0"?>

< vxml version="1.0">

VOICEXML ELEMENTS

 Element Purpose

<assign> Assign a variable a value.

<audio> Play an audio clip within a prompt.

<block> A container of (non-interactive) executable code.

<break> JSML element to insert a pause in output.

<catch> Catch an event.

<choice> Define a menu item.

<clear> Clear one or more form item variables.

ARCHITECTURAL MODEL

PRINCIPLES OF DESIGN

VoiceXML is an XML schema. For details about XML, refer to the Annotated XML

Reference Manual.

1. The language promotes portability of services through abstraction of platform

resources.

2. The language accommodates platform diversity.

3. The language has a control flow mechanism.

4. The language enables a separation of service logic from interaction behavior.

5. The language provides ways to link documents using URIs, and also to submit data

to server scripts using URIs.

IMPLEMENTATION PLATFORM REQUIREMENTS

• This section outlines the requirements on the hardware/software platforms that will

support a VoiceXML interpreter.

Document acquisition.

Audio output.

Audio input.

DIALOGS AND SUBDIALOGS

Forms. Menus.

Transitioning between documents in an application

EXAMPLE

Example asks the user for a choice of drink and then submits it to a server script:<?xml version="1.0"?>

<vxml version="1.0">

<form><field name="drink">

<prompt>Would you like coffee, tea, milk, or nothing?</prompt>

<grammar src="drink.gram" type="application/x-jsgf"/>

</field>

<block> <submit next="http://www.drink.example/drink2.asp"/> </block>

</form>

</vxml>

APPLICATIONS OF VOICE XML

Voice portals.

Location-based services.

Voice alerts .

Commerce.

CONCLUSION

• VoiceXML is designed for creating audio dialogs that feature synthesized speech,

digitized audio, recognition of spoken and DTMF key input, recording of spoken

input, telephony, and mixed-initiative conversations.

• Its major goal is to bring the advantages of web-based development and content

delivery to intera.

• Instead of using a PC with a Web browser, any telephone can access VoiceXML

applications via a VoiceXML "interpreter" (also known as a "browser") running on a

telephony serverctive voice response applications.