My 16 months doesn't talk much ,he doesn't call mama or papa even though sometime he may try to say it when we ask him to.when I ask him to repeat some words I can see he tried to pronounce but it doesn't sound like the word or it sounds all the same when I ask him to try to speak different words,he babbles a lot .my first born wasn't like that I didn't want to get worried but can't help worrying now , anyone whose kids seen speech therapist , how young can we start? Thanks