my son is 20months old now. he is not talking well. he is saying Amma appa Thatha paati Apple ball car auto no no Tha like tat. but he s not saying any other words as well. he s understanding everything that what we r saying r asking to him. but he s getting trouble t talk.. when I asked him to say this means he will say ah mm like this... my cousin's son is same age, he s talking nd answer so gud but my son is not talking lik him.. so I'm worried.. when he will talk fluently ..