Oh, this is very simple!

First, tap on the Settings button, the gear icon on the right upper corner of the main screen. Then, you'll be able to toggle on or off the "Sound FX", which are the Characters voices in-battle, for example, and the "Music", which are the amusing songs on the game main screen and the battle!

If you have any issues to do this, please, check our article "How to contact us" and send us a report!