When configured as a numeric keypad, the first touch sits directly on the number "5." Swiping it to the upper right produces a "3," and to the lower left a "7." Each time, as the finger passes over a number, the phone vibrates, and when the finger is raised, indicating that a selection has been made, a computerized voice repeats the number.

To navigate through the phone's address book, a user touches the screen to produce a circular set of eight letters. (See a video of the interface in action here.) Swiping to the upper left, where the "A" is located, opens a new circular menu of eight more letters: "B," "C," "D," and so on. Employing this approach, says Raman, a user only needs to move his finger, at most three times, to access any letter.

Android also supports text-to-speech capabilities so that developers can design apps to verbalize the text that appears on a screen, but this doesn't help users input information.

Microsoft's Baudisch says that it will be exciting if these sorts of interfaces are to find their way outside of research labs. "It's wonderful that [the Google researchers] are doing it, and they implemented it nicely," he says. "Marking menus are great, and it's time that somebody puts this into the products that it belongs in."

Raman acknowledges that it's still early days for eyes-free interfaces and that there is much to learn about what consumers will find useful. One possible way to improve eyes-free interactions would be to have the phone predict a user's intent, he says. For instance, a person might regularly check the arrival times for a bus after work each day. Given that, the phone could respond to a certain gesture, such as tracing the letter "B" after 4:15 on weekdays, by telling the user when the next bus is due.