Mail
  
  
  Operator
  
  
  
 
 
 

As you can see, the choice options within the menu call additional VoiceXML "routines" that define further tasks. The element handles every response that's not either a "Mail" or an "Operator" command. In this case, it includes a command that simply orders the server to replay the items in the prompt list.

By no means is this a comprehensive tutorial but it should give you a feel for the way in which voice commands are processed and defined on the server. Obviously, this sort of application would have to factor in scalability and server loads given the processing power required to continually do speech-to-text conversion. In addition, traditional server development tasks (database/messaging system access, spatial queries, etc.) would need to be developed to interface with prompt choices.

Potential Applications

The potential applications of this technology abound. Currently, voice "portals" such as TellMe, Quack, and BeVocal are springing up to offer voice access to stock quotes, movie and restaurant listings, and daily news. Just as traditional Web portals redefined themselves over time into personalized services, these voice portals will eventually offer access to your email (to both check and send emails using your voice!), . Ironically, voice technologies are over a century ahead of the Web in one area: instant messaging (isn't that what Alexander Graham Bell's original phone call basically amounted to?!?).

These voice-related technologies will also be among the first location-based services to appear on the market because of the mobile nature of the end user. For instance, currently the TellMe portal can automatically retrieve movie listings for the nearest theater based on the number you are calling from. For the majority of location-based applications, this type of service is accurate enough. In the future, one could imagine integration with the FCC-mandated E911 positioning or even a GPS in the handset for driving directions that actually talk you through the twists and turns required to reach a destination.

Benefits of Voice Processing

Separate from the discussion of VoiceXML is a look at the benefits of voice processing technologies in general. Despite the advent of technologies such as WAP, the fact remains that accessing textual content over a small phone display is difficult and, in some applications, rather unnatural. When adding in any amount of data entry over the phone, it quickly becomes an impractical interface. Voice technologies, on the other hand, take advantage of the very interface that phones were designed to server and will undoubtedly be accepted more readily by the general public. VoiceXML, specifically, is a well-structured, uniform way to build logic trees that customers can use to access the information of interest to them. Look for tools and services based on VoiceXML to become increasingly popular in the near future.

Perhaps the biggest disadvantage of voice-based technologies is the rigid structure that they impose on the end user. While a textual interface (i.e. WML) can support popular tools such as search engines and online browsing of catalogs or information, voice technologies are much better at delivering a specific pinpointed bit of information to an end user (i.e. a stock quote, a movie time, a restaurant location, etc.). In addition, while convenient, using a voice portal such as TellMe can be maddeningly slow when forced to drill through several layers of options before finding exactly what you want. One interesting combination of the textual interface and the voice interface is the tool known as a "voice browser" (for a demo of a popular voice browser, visit Conversa). A voice browser allows the user to "speak" links to quickly traverse through textual content, which may be a great compromise...particularly in automobile- or hands-free type of applications.

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