At 1 years old they start to walk unless they are late bloomers at 2 they start to talk more at 3 they are more clear in words and know how to tell their parents that they need to go the bathroom at 4 well they can start preschool than there it is.
My experience is with my 3 year old brother... at 1 he started to crawl, at 2 he learned a bunch of animal names and learned the abc's and he learned the numbers up to 10 and he knew how to walk(late bloomer) than at 3 he is potty trained. Hope this helps
