SANDY — It's common for video gamers to mutter or yell at their game screens, but more and more, those words are actually helping them play.

Thanks in part to Sandy-based Fonix Speech Inc., gamers can tell their characters what to do rather than machine-gunning their fingers to nubs on the controller buttons.

"Go! Go! Go!" Fonix Speech's IT manager, Joe Shepherd, chimed into a microphone during a demonstration on Monday, and a moment later the characters in his attack group went, went, went. They also followed other commands without question: "Assault!" "Infiltrate!" "Hold position!"

In another game, a SWAT team likewise followed its commander's instructions: "Breach door!" "Secure!"

"What we've found on these games is that by having the speech interaction, it actually puts you further into the game," said Lynn Shepherd, Joe's father and vice president of product development for Fonix Speech. "One of the taglines we use is 'Get in the game.' And speech psychologically really brings you in a lot more."

With already more than two dozen game titles using Fonix' VoiceIn technology, the company is awaiting the pending launch of "Tom Clancy's EndWar," which is expected to have a command vocabulary topping any of its previous games, the best of which have a vocabulary of about 70 commands.

"These guys (Ubisoft) have put a lot of work into the user interface," Lynn Shepherd said. "They're kind of taking a big step out in front with what they're doing with voice."

Fonix Speech has been working with Ubisoft on the "EndWar" game for about six months, and while details of the game are scarce even for Fonix Speech officials, the voice command element apparently works well.

An "EndWar" review at IGN.com notes players often struggle with unit selection, command and camera control.

"All of this can be done with the controller in 'EndWar,' but you can also use your voice to play the game," the reviewer noted. "With the press of a button, you can order attacks, swap your vantage point or commandeer control points. The exact same commands can all be issued simply by talking — and it works. Aside from the times when we mumbled, the game had no trouble recognizing what we said."

Expected to be released this spring in several languages, "EndWar" also is expected to break another video-game barrier by having voice commands that work as well on game consoles as they do on the PC.