Learning to talk is a far more complicated task than most people think, but babies' brains are dedicated mostly to it. Babies must learn how to use more than 225 muscles in their mouths and throats in order to talk.
Babies make random sounds apparently because they feel good.
All babies who do not have speech impediments manage to make all the sounds characteristic of all languages in the world during this stage. The baby accomplishes semi-conscious control of the sounds which are characteristic of his own language as well as hundreds of others. The family reacts to these sounds with pleasure. Early in this stage they may be induced to mimic the sounds made by parents, or especially by brothers and sisters. They often imitate these sounds and are helped by an enthusiastic and loving response from their caretakers.