We propose a technique called voice augmented manipulation (VAM) for augmenting user operations in a mobile environment. This technique augments user interactions on mobile devices, such as finger gestures and button pressing, with voice. For example, when a user makes a finger gesture on a mobile phone and voices a sound into it, the operation will continue until stops making the sound or makes another finger gesture. The VAM interface also provides a button-based interface, and the function connected to the button is augmented by voiced sounds. Two experiments verified the effectiveness of the VAM technique and showed that repeated finger gestures significantly decreased compared to current touch-input techniques, suggesting that VAM is useful in supporting user control in a mobile environment.