Nuance Communications, the speech-recognition technology company, said it has agreed to acquire BeVocal, of Mountain View, Calif., for $140 million.

The deal allows the Burlington, Mass.-based Nuance, which dominates the speech-recognition market, to extend its reach into mobile calls, where BeVocal’s customers include carriers like Cingular, Liberty Wireless, Metro PCS and Virgin Mobile. It comes at a time when Tellme is making headway in mobile voice search (though Tellme relies on Nuance’s underlying speech-recognition technology).

Mobile phone subscriber numbers continue to ramp up. Global subscribers are expected to reach three billion by 2010, up from two billion this year, Nuance said in its statement.

Nuance said BeVocal also offers a way to deliver services through additional channels, such as Web and SMS.

BeVocal has raised more than $80 million from ArrowPath Venture Partners, Mayfield Fund, Technology Crossover Ventures and USVP. Transcosmos and Bellsouth, early investors, did not reinvest after 2001 in the wake of the downturn.

(First posted 2/22)