He vocalises more and more and makes all sorts of noises which mean nothing and yet his speech is developings all the time.
By six months he is constantly babbling and one can discern some semblance to sounds like ‘na-na, pa-pa’, etc.
From nine months to a year, the sounds increase in number and the baby may use one sound for his mother, another for milk and yet another for water, and so on.
Between one and two years the vocabulary increases gradually and the child is able to express himself and talk fairly clearly.
Some children speak baby talk longer than others, which is quite normal. It is better to use proper words while taking to the child rather than baby talk.