One important question now is When the best time for children begin to learn English Language. Most experts believe that when a child is introduced to a second language at an early age their chances of becoming more proficient in the target language will be higher. However, it is not necessarily true to say "the earlier the better". It is suggested that the most efficient time to learn another language is between 6 and 13.
However, children who learn in pre-to-early teens often catch up very quickly with children who learn from an earlier age. Also this does not mean that languages cannot be learnt later in life. The experience and environment at school and how language is taught and practiced play a vital role in language acquisition, regardless of how young or old the child is.
Whatever the age, when children learn a second language, they develop skills that will help to create opportunities in their future. They acquire the lifelong ability to communicate with others under diverse circumstances. Indeed, regardless of the level of proficiency, learning a second language and learning about different cultures generally broadens a child's outlook on life. It also opens up alternative educational and career opportunities.
adaptation from : The child as a learner