The Search for Voice Activation

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Voice-activated systems, while getting better, can still sometimes get the answers wrong, explains Morgan. The software matches the voice input to a number of possibilities and often asks the user if the system's highest-ranked word was the one he or she intended, or it might say the word was unintelligible. These systems work best when the algorithm needs to access only a small dictionary, he adds, such as ring-tone options, movie listings, or phone-book contacts.

That methodology, though, would be impractical for Web searches, since it's impossible to limit the search dictionary while providing access to the eight billion-plus websites that Google searches.

Google's voice search patent approaches the problem by taking a step back from simply plugging standard voice-recognition technology into standard search technology, says Morgan. Instead of trying to accurately predict the single-best guess about what a person is saying, the technology would take a handful of word and phrase possibilities and throw them at the powerful Google search engine. In this way, the voice search system may not need the most accurate speech recognition technology. Instead, it relies on Google's strength -- its search algorithm -- to supply the most likely result for a number of possibilities.

This strategy of outsourcing the translation and searching to remote Google servers has its benefits, says Jordan Cohen, senior scientist at SRI International in Palo Alto, CA. It reduces the level of complexity in the software on the phone, and therefore wouldn't use as much processing power, memory, or energy. Instead, it relies on the strength of the network -- and some faith that the technology would be able to deal with the uncertainty of both vocal input and an intended search. If speech technology is instead confined to the mobile device, Cohen says, the software can "count on the person to fix things up" when the algorithm can't find the most suitable word.

Because mobile voice search has barely begun to take form, it remains an open question whether Google's approach will be employed -- or produce the best product. But the market for mobile search in general is "going to be immense," says Cohen. "The Google patent is an attempt to stake out a claim in that space."