which stage of life is the most proper one for learning second or third language?

In the first years of a child's life many important milestones are reached. By the end of the first year a baby will have already acquired some social skills. By the age of two or three, the infant has reached the toddler stage. In terms of social skills, this means, he/ she become more independent. Between the ages of six and twelve, a child reaches what is termed 'middle childhood ' and they will stay in this phase until they reach adolescence. adolescence is the final stage before adulthood.