Babies are learning language from the moment they are born. At first, to a newborn baby, speech is just sound. Then, day by day, they learn that the sounds have meaning. This process depends on how much people talk to them. Every time you talk, sing, or point to what you are talking about, your provide clues to the meaning of what you are saying. You are providing important information to their brains about how language works.
As your child develops, talking with them and answering their questions is a way to teach them about the world. By talking with them, you will also get to know the fascinating person they are becoming!