I hope that is all it is and he isn’t used to speaking so much either. He must be so pumped up and that is exhausting.
He can eat some of his mama’s cooking and spring right back!
He’s running on adrenaline now. Eventually he’ll come down to earth and learn how to pace himself and protect his voice. He has a well pitched speaking voice and is using it correctly, (IMO as someone who has studied public speaking).