DS is 5 months and has just found his voice - loudly! He shouts/squeals/shrieks at the top of his voice, constantly. He's not tired/hungry/needs nappy/windy, just likes the sound of his own voice! Trouble is, it's such an ear-splitting shriek it's giving me a thumping headache :( He doesn't understand 'no' or a tap on the cheek, or anything. He has a dummy and shouts out the side of it! At my wits end what to do. Any suggestions?