LAS VEGAS--Yahoo today debuted a new version of its mobile oneSearch service, led by the addition of technology that lets users search the Web from their phone using simple voice queries.

Yahoo is in a heated battle with Google and Microsoft to dominate mobile search, a still-nascent market that nonetheless holds as much – if not more – promise that desktop-based Web search.

“We don’t believe any one company, neither Microsoft or Google or Yahoo, or even one carrier, can drive [this] alone,” said Marco Boerries, executive vice president of Yahoo’s Connected Life services. “We are trying to carve out a place for ourselves.”

For Yahoo, that “place” includes a mobile-optimized Yahoo.com start page, oneSearch, a mobile search application; oneConnect and onePlace, related apps for tracking mobile content and social networks; the Yahoo widget platform; and a monetization engine for generating revenues for itself and its partners.

To fuel its new voice-based service, Yahoo today revealed a $20 million investment in Vlingo, which provides the voice-recognition technology at the heart of the new version of Yahoo oneSearch. Yahoo said it has exclusive rights to use Vlingo’s technology in mobile search. Yahoo and Vlingo are showing the new voice-enabled service on the CTIA show floor.

The service lets users search for anything, including flight numbers, restaurant locations or Web site names by simply speaking the phrase. Yahoo stressed that its voice-based search returns a wide array of results, whereas many early voice-based search apps limit users to certain categories, mainly local business listings.

“We believe that is not the right answer,” Boerries said. “What we have done is found this technology [in Vlingo], and we combined it with our oneSearch service.”

Blackberry users can download a version of the voice-based search starting today at m.yahoo.com/voice. Yahoo aims to roll out the service to more than 500 devices by the end of this year.

Google is delivering voice-based local search via its GOOG-411 free service. Microsoft acquired TellMe Networks to make voice-based interfaces a key part of its application and search strategy.

In addition to voice-based search, Yahoo introduced a handful of additional mobile search features, including:

• Semantic Search. Yahoo will work with publishers to make it easier to integrate relevant content into oneSearch results, resulting in a more “open” model for mobile-based search. For instance, a oneSearch query for a specific airline flight would deliver information right from the airline site rather than a list of search results. Yahoo made a similar move with their Web search product this year, and the two services – Web and mobile search – share the same APIs, said Boerries. “It’s truly open; [publishers] don’t need a business development deal [to get their content into the semantic search]. It’s a point-and-click license. This is first and foremost about traffic acquisition for the publisher.”
• Mobile Search Assist. Yahoo is making it easier for users to type in search queries on their phones, including predictive text completion and contextual recommendations, beginning with the Apple iPhone.
• Idle Screen Search. Yahoo previewed a new service that will let users search via a oneSearch search box integrated directly into the mobile device main screen.