A.D.
We have five children and all went through this stage of independence/wanting to hear themselves and see your reaction!! We practiced with our kids on quiet time, normal and loud. Before going outside I would say, alright it is alright to be LOUD (raise your voice some) because we will be outside. Then practice at play time together about talking normal, when the mood is not tense and relaxed and fun. Then when going to a store/outing talk about it while still in the car, you have to have a little voice. I wish you well and just always practice/talk to your child in a normal tone of how to conduct himself, especially when he is not yelling. Consistency is key!!