Kids Learning to Speak
There is no one point at which your child learns to talk.
There is no one point at which your child learns to talk. By the time you hear the first word coming out of her mouth, she has already spent months playing around with sounds and their meanings. Each child learns at his or her own pace, but virtually everyone follows the same stages.
It starts with crying, obviously. That’s the first sound that comes out from your baby’s mouth. A few weeks later, vowels make an appearance, with sounds like aah, ooh, ee. At six months, consonants enter, and they are paired with vowels, for sounds like boo and da. This is when you’ll rejoice at hearing your child say things likes dada or mama. In fact, it’s just sorting out sounds, without attaching any meaning to it just yet.
With her first birthday should come her first word with meaning. It is likely to be something like doggie or eat or see, as opposed to functional words like and, the, or of. A few months later, the first sentence will come out, most likely a combination of two words she’s been using for a while now, like see dog, and a few months after, more complex sentences like big doggie run fast. The sentence won’t have any function words in them.
At that point, the only thing left is to learn the function words, different sentence forms, and more complex sounds like str. By the time you send your child out to kindergarten, she will know the majority of the rules of language. After this, it’s just about building on the vocabulary and learning how to combine sentence types in new ways.
Reference:
http://www.linguisticsociety.org/resource/faq-how-do-we-learn-language