Google is bringing its recently upgraded voice search features to iPhone and iPad devices as it tries to solidify its growing mobile search business and ensure future ad revenues.

The mobile search space is growing quickly as consumers increasingly use mobile devices to conduct an Internet search, with one of the most highly visible developments in the past year being Apple?s introduction of voice search service Siri. Google?s own updated voice search comes at a time when Apple may be looking for a way to monetize Siri and encroach on Google?s mobile search ad revenue.

?Undoubtedly, Siri has converted a number of smartphone users to iOS and has persuaded many existing iPhone owners to upgrade to the iPhone 4S,? said Matt Grebow, senior manager of search marketing at The Search Agency, Los Angeles.

?Aside from selling more phones, Apple never figured out a way to monetize the technology itself,? he said. ?Apple?s announcement in June that it would be supplanting Google Maps in iOS 6 with its own mapping service provided the first hints of a potential voice-powered local ad service.

?Google?s Knowledge Graph is designed to keep searches within Google?s Web properties. Smartphone users have continued to grow increasingly comfortable searching from their phones, and Google knows that solidifying its mobile search base is essential for its future ad revenues.?

More relevant search results
Google?s voice search uses speech recognition technology and pairs it with its Knowledge Graph to interpret questions and speak the answers back as a full sentence when possible.

The news that the service will be coming to iOS was made as part of a series search-related announcements from Google, including that it will expand Knowledge Graph, which uses a database of more than 500 million real-world people, places and things to provide more relevant search results.

The new Google voice search services have been available on Android for a few weeks and will become available on iOS soon, enabling iPhone and iPad users to tap the microphone icon on the Google app for these devices and ask their question. The question appears on the screen as they ask their question.

For example, users asking ?What movies are playing this weekend?? will see a list of the latest movies in theaters nearby with schedules and trailers.

Siri has advantage
As Google and Apple continue to compete for dominance in the digital sphere, the battles are increasingly been fought in the mobile space.

Siri is one way that Apple is trying to compete with Google in search, where Google is dominant. Apple continues to advertise Siri aggressively hoping to attract consumers to the iOS platform.

However, despite Google?s upgrades to its voice search services, Siri may still offer the better user experience.

?I think Google offers competition in voice search, but not a threat,? said Carl Howe, vice president of research and data sciences at Yankee Group, Boston. ?Siri is built into the iPhone, whereas consumers will have to download the Google app.

?As such, only a fraction of consumers will ever see Google's offering unless it takes off like wildfire, and frankly, the difference in capability between the two offerings would have to be huge for that to happen,? he said.

?Most people at least start with what comes with the phone, and that gives Siri a huge advantage.?

Better experiences needed
By bringing its upgraded voice search features to iOS, Google is hoping to further bolster its dominance in search. With Apple?s iOS powering one-third of all smartphones sold, this is a large number of mobile users for Google to leave in Siri?s hands.

The competition over voice search could end up being a good thing for consumers, who have been enamored of the idea of being able to ask their smartphones a question and getting a response but less than thrilled with the experience so far.

?For Google, Siri has been less a direct competitor to Android than a troubling search trend,? The Search Agency?s Mr. Grebow said. ?Introducing a Siri-like voice app for iOS enables Google to reclaim a large number of mobile searches that it otherwise wouldn?t see.

?The jockeying for voice-search supremacy between Apple and Google will push both companies to improve their technologies, which, in the end, should benefit all smartphone users,? he said.

Apple and Google both face challenges in gaining acceptance for their voice search services as some consumers still may not be ready to change how they conduct a search.

Additionally, the response to Siri so far has not been all positive, with some users complaining that it does not work as advertised.

?Societally, I don't think we're quite at the point where it's considered normal to have a conversation with your phone without a person at the other end; people who observe you will just think you are weird, and that's a big challenge for voice technology,? Yankee Group?s Mr. Howe said.

Final Take
Chantal Tode is associate editor on Mobile Marketer, New York