'Talking back' is, I think, something that most all parents have had to create rules around for their children. Maybe there are kids that never have done or at least attempted (in the very best of circumstances) this most basic act of parental disrespect, but I am certain that if they do exist, that it's not on this earthly plane.
As a father to my first child, I had not had the 'pleasure' (haha) of this kind of experience of a little person, whom I am supposed to be looking after and caring for, tell me "No" flat out, when I request something of them or deny something of them for their own best benefit and good. It can come as quite a shock when all you-- as an adult male living in the modern adult world--have known has been mostly open, respectful and civilized adult conversation, to be confronted with a little person that challenges your (almost) every decision or request pertaining to them. They are all so sweet and lovely until they aren't so much, which for me has been from a little over her third year up to the present. She'll be four years old this next month.
At this point she exerts her opinions and ideas rather strongly, which is fine, but when they conflict with her mother's and mine, and then she pushes beyond that, is when things can become a little tedious. The 'weathering' of her whiny resistance can be tough. It takes a lot of energy to withstand these persistent, pushy, fast, and energetic little people.
We're making it, but the process hones us, her parents, just as we are honing her. Every once in a while I am still shocked by it: by the constant, relentless pressure exerted on the boundaries of 'good' behavior. Parents really do have to teach everything, be consistent and fervent in those teachings, know why and be able to translate it (I can see this coming down the road) all when needed.
It's a good job, but in some departments and at some times it totally takes All You've Got.