It is possible to have 'conversations' with a child from the very earliest age. It does not matter how simple or babyish the conversation is. What matters is 'bathing the child in words'. The child needs to respond to words and sounds and to see others respond to his or her own attempts at sounds and words. When a child begins to make sounds, words, and sentences, parents should show their delight and encourage the child to build on the things that have been learnt.
Children learn to speak at different ages.
In general, they begin to talk from about the age of one and can use complete sentences by the age of four. By age six, all the basics of language have usually been learned. Encouragement and practice during these first six years is very important to the child's later success in learning to speak, read and write, and to do well at school. There is no difference between the physical, mental, and emotional needs of boy and girl children. Both have the same need for play and the same capacity for all kinds of learning - and both have the same need for expressions of love and approval.