To turn the sound off, go to the game screen. This is the screen that shows your pet going about his/her daily activities. Then, press the mode button. You should be on the clock screen now. To the right of AM/PM, you should see a little bell. When this bell is present, that means your sound is on. Press the left button to make the bell disappear. When the bell disappears, your sound is off. To turn the sound on again, press the right button in the clock mode. Hope I helped!