It's normal, it's nothing to worry about my little brother didn't start talking for a while. My brother learned how to talk by listening to us and he would copy. Now he talks all of the time, It's actually quite annoying.
No don't worry every child is different my 23 mth old barely says like 20 words because her older sister talks for her and babies her so you just have to work with them I won't give her what she wants until she at least tries to say it first. Like please and thank u she won't get her Juice until she says please. You just have to work with them ;)