I would answer this with the "sweet spot" response.

I believe that kids learn more quickly and easily what they are developmentally ready to learn. Pushing them to learn something--like reading--too early for that particular child carries a cost, in that the child is not learning other things that s/he is ripe to learn because the child has to work so much harder at the skill. This seems counterproductive to me. Why swim upstream?

So I'm not a fan of forced early learning, of letters or math or anything. If the child is interested, then that indicates a readiness, and then I'm all for it. I really believe that child-led learning is the way to go.

With that said, unless I suspected a case of child abuse, I wouldn't say anything to another parent about their choices. Parenting is hard enough without being second-guessed by others.

Kriston