Check whether your Tamagotchi model has a sound or mute option in the settings
Press the A and B buttons together on many models to access the sound menu
Select the mute or sound-off option if available
On some models, hold the A and C buttons together to toggle sound
On older models, try pressing the A and B buttons at the title screen
If your model has no mute setting, lower the volume by covering the speaker lightly
Refer to the specific model manual for the exact mute method