Google said it sees voice search as a crucial component of its strategy to dominate the mobile web search market.
Speaking at the Web 2.0 Expo in San Fransisco, Google's vice president of marketing, Vic Gundotra, said he believed voice search to be core to its business, the BBC reported.
Gundrota said the technology had improved from the early days, when Google's offering had difficulty understanding accents other than American.
"I get the advantage of looking at daily voice queries coming in and it's amazing"&brkbar; it's reached a tipping point," he said.
Launching the service on the iPhone led to a 15% jump in accuracy, because Google collects and analyses data from every user, he added.
Google's voice search service is also available on the Android-powered T-Mobile G1, and for BlackBerry handsets as a free download.