Child Development milestones
At 2 Months a baby is expected to start smiling, looking at parents, reacting to noises, following objects with eyes and to push up when on stomach.
At 4 months, a baby is expected to start rolling over, bringing objects to the mouth, recognizing people, fearing strange people, babbles, showing emotion, and sitting down with support.
This is the time a baby would begin to learn how to communicate with the people around them, they start to crawl or pull themselves up to stand, can move things from one hand to another, makes a lot more sounds, plays games like peek-a-boo, and can grasp small foods between thumb and finger.
At this points, a baby will begin trying to repeat words, start to do things like wave bye, understanding simple directions, starts to use things like a spoon properly, puts things in containers and take them back out when they want/need them, at this point they may even begin to walk, and can even find hidden objects.
1 year to 18 months
At the one year point, the baby will begin to have temper tantrums, play pretend, the vocabulary will increase greatly, has the ability to point out body parts, scribble, walk up and down steps, undress themselves, and even drink from a cup.
At this point they will begin to be more independent, play with other children, stand on their tiptoes, running, starts to speak in short sentences, starts to show hand dominance, sorts objects, and will even be defiant, follow two step directions, and kick a ball!
At three years of age, kids will start to carry on conversations, ride a tricycle or a bike completes puzzles, begins to play make believe, dress and un dress themselves, thrive with routine, walk up and down the stairs, discuss their likes and dislikes, recognize numbers and colors, tell stories, be able to hop and stand on one foot, catch a ball, and even be able to do a somersault.
At four years old, a kid will begin to think symbolically, expand their vocabulary lots, develop a memory and imagination, and start to understand the difference between the past, present and future.