When my kids first started childcare, I realise suddenly that they are speaking very loudly. It happened with DD and again with DS. I realise then that in a childcare the noise level can be quite high especially during play and interaction time so the child tends to speak very loudly. My nephew too, speaks very loudly. He is naturally loud, I think due to him being looked after my his granparents when he was younger and they talk very loudly and the TV is forever blaring in the background. Then when he went into childcare, also noisy so he continues with that volume. And there was once we noticed that he was even louder then ever, we eventually realised that his allergies were acting up and the backed up mucus is affecting his hearing. Once that cleared he went back to his normal loudness. I guess there is no fast solution, only way is to constantly remind them to keep their volume down. Eventually they become more aware. There were times when DD will start speaking at a pretty loud volume and sheepishly say I very loud hor.