Most world renowned psychologists and psycho-analysts believe, that the early days in the child's development are instrumental in making him, what he becomes when he grows up. The child goes through several ages and stages of child development. This can be explained with the example, that between the age of 6 months to 18 months, the child goes from vocalizing via intonations to having a 5-20 vocabulary. Many such developments take place at a rapid pace, if the correct environment and child care is maintained.
As I have already started off on this, the child's vocabulary building starts at the age of 6 months. Being a very young age for the child, he is highly receptive of his surroundings. So, be it the right word or the wrong one, due to the child's development, he will pick it up.
In detail, by the age of 6 months, the child will be able to communicate using tones and sounds. He will know his name and will respond on hearing it. In fact, if he hears any human sound, he will try to see the source of that sound. More so, the child will be able to distinguish between a friendly or an angry voice and tone.
By the age of 1 year, the child's vocabulary database is in order and has at least one word in it (mostly, more than that). The child is capable of following simple instructions with visible cues. He knows the difference between tones and uses them. He is also aware of the importance of speech by this age. This way, his development goes to the next level.
By the age of 18 months, the child has around 5-20 words in his vocabulary. The more you speak to the child (clearly) the more words he will learn at this stage. The children will show a tendency to develop a more emotion based vocabulary, first. This is normal primal behavior. As, it is important for anyone to be able to express emotion before concepts. The child will be more capable to follow commands without visible cues. Don't you see growth already?
By two years of age, the child's development reaches a high level. He is capable of naming the objects that surround him in the regular environment. He can use at least two out of the three prepositions: in, on and under. If he can use all three, you have a potential genius at hands. The child also shows an ability to combine words and make a short sentence. However, the sentence will have around 2-3 words. Majority of the child's verbal communication will be commonly understandable. This is because, the child's vocabulary, by now, would have built up to 150-300 words. More than 10 times what it was 6 months ago, right? There, most probably, will be a confusion between 'I' and 'me' and the tones and pitch may not be in control. However, the words my and mine will start to appear in regular vocabulary. More so, you can start playing the "show me your eyes" game, they know the basic parts of their body!
Now, between the ages of 3 and 4 years, the growth rate increases at a much more rapid pace. The child will go from knowing pronouns correctly, to knowing names of familiar animals, like dog, cat and rat. The child knows 3-5 prepositions, knows their meaning and can use them, pretty much flawlessly. At the age of 3 years 90 % of the child's verbiage is intelligible and by the age of 4 years, he starts indulging in creative make belief. The understanding of reference to context starts and gets stronger between these ages. In fact, by the age of four, the child should be able to give his sex, his name and his age. Further training can capacitate him to give his address, school and telephone number, as well. Frequent repetition can facilitate that.
By the age of 5 years, the child will be completely capable of giving his details like address, school and telephone number. So, make sure you give him the knowledge that "do not talk to strangers". He will be capable of making sentences that are about 9 words long and will have simple time concepts like, today, tomorrow and yesterday, mastered. On the whole, his speech should be grammatically correct. To this end, you need to make sure that you have grammatically flawless language when speaking around him. Remember, even now, he will learn from your example.
Post the age of 5 years, up till the age of 7, his development will carry on along these lines. Since, these years are so important from the communication aspect, there is a general physical development, as well. Let us see those.
Before we get into the timeline of the early child development, you need to note and keep in mind, that the child's development will take place only if he is ready. So, do not force the child, however, encouragement could be a healthy way to start the process. There is a thin line between force and encouragement that you need to be aware of.
Between the ages of 2 months to 4 months, the child will be able to lift up his head, roll over and sit propped up with back rest, without falling over. By the age of 6 months, he will be able to sit up without support. However, he may lose his balance at times. By 7 months, he will start making attempts to stand up with support and by 9 months, he will combine standing up with walking, as well, with support. This is where you bring out the camera.
By the age of 10 months the child will try to stand on his own without support for some time. Then, by 11 months, he will gain more confidence and will be able to stand without support for longer. By the age of 1 year, he will be able to walk without support, as well. Nonetheless, keep a keen eye on him, as balance could be occasionally lost. In fact, many psychologist believe, that by this age, the child can gauge distances and heights.
By 13-14 months of age, the child will be able to walk backwards with little or no support. This is a great way to build the required muscles and should be allowed, occasionally. By the age of 17 months, the little toddler will be able to walk upstairs, with little or no support. Further, by 18 months of age the child will be able to manipulate things with his feet, as well. Like kicking a ball while walking.
Physical growth for the child carries on till puberty at a similar pace and then slows down drastically post puberty.
As a very good phrase goes, "simply giving birth, does not make one a parent". It is very essential for parents to be aware of the growth patterns and do the best they can, to make sure they facilitate as much physical and psychological growth, as possible. Constant communication with the child is one of the best ways to ensure child development. This is where I sign off! Happy parenting!