Google's voice search on the iPhone may be revolutionary, artificial intelligence experts say. (Ed Ou/Associated Press)

Google Inc. is adding speech-activated search to Apple Inc.'s iPhone, a move experts believe may finally enshrine voice-recognition as a mainstream technology.

Apple is poised to release Google's voice-search application as early as Friday, according to the New York Times. The company told the newspaper the free software will be available through Apple's iTunes "app store" and will let users speak search queries into their iPhones rather than type them out using its touch screen.

The application is considerably intelligent, according to the Times, and can answer full questions such as "Where is the nearest Starbucks?" or "How tall is Mount Everest?" The query of "What is the best pizza restaurant in Noe Valley?” returned a list of three restaurants in the San Francisco neighbourhood, complete with reviews from Google users and links to phone numbers and directions.

The queries are converted into digital sound files and transmitted to Google's servers, which process the request and deliver the answers. Artificial intelligence experts said the company's capacity to store and analyze vast amounts of data may give it an advantage over previous attempts at ubiquitous voice-recognition.

“Whatever they introduce now, it will greatly increase in accuracy in three or six months,” Raj Reddy, an artificial intelligence researcher at Carnegie Mellon University in Pittsburgh, told the newspaper.

Voice-recognition technology is standard in most phone answering systems, but many have trouble dealing with free-form speech and offer only limited responses. Fuller voice-recognition software has also been produced by other companies including Corel, Microsoft and Adobe for years, but it has remained a largely niche technology.

Google executives told the Times that the company's advantage lies in the trillions of search queries users have input over the years, which allowed it to build a statistical model of the way words are strung together.

The company also said the free application fits with its philosophy of providing services to consumers for free because it will raise the value of advertising with Google. The company also has plans to make the service available on other phones.