Ds2 (and god knows I don't often post about the poor boy) is 21 months old, and over the past 2 weeks has been getting louder and LOUDER. Now he is lying in his cot talking to himself ("Nat nat nat! Mmmmmmm nyum nyum! Nanarrrr!") so I wondered if this is the start of a 'speech explosion'? Ds1 never made a sound at this age but he didn't develop typically.