My 14 month old has started screaming whenever he feels like it - be happy, upset, sad etc. It never comes with a tantrum etc he just sits casually and does it.Its very loud and draws attention. Its really getting me down and i hate going places with him now because of it. Ive tried telling him "bad" in a stern voice, ignoring it and even putting my hand over his mouth when he does it but nothing has stopped him. i could just run away when he starts. Any advice? does other children do this?never heard any