Two voice powers are linking up, combining one's expertise in development tools and standards-based applications with the other's prowess in Web-based tools and natural-language apps.

Specifically, Intervoice ( INTV) is buying Edify, a provider of interactive voice response technology, from its parent company S1 ( SONE).

"This merger will mark a turning point in the speech industry," said Mitch Mandich, CEO of Edify. "Two financially compelling market leaders are coming together to create an even stronger company that will benefit from its enhanced capabilities to deliver speech solutions to a growing market."

The deal is valued at $33.5 million in cash. Over the last four fiscal quarters, Intervoice and Edify had combined revenue of more than $200 million.

"The joining of Intervoice and Edify will bring unmatched expertise in providing customers with award-winning, standards-based automated information solutions," said Bob Ritchey, president and CEO of Intervoice.

Intervoice sells voice-automation software and other products. The company's shares were falling 33 cents, or 3.7%, to $8.72. S1 was gaining 29 cents, or 7%, at $4.41.