I’m not hearing sound on the play screen
Possible causes are:
Sound is turned down on the device
Turn the sound up on the device.
The character that you are playing back is marked as your character, and you have the ‘Play’ (iOS) or ‘What to do with my lines'(Android) setting in the Play menu set to not play them.
Either change the Play option in the menu to ‘my lines’ (iOS) or ‘play them'(Android) or go to the Characters screen (from the script screen select the script then press > then press the Characters button) and make sure that only your character has a gold star. Stars can be toggled by pressing them.