The age of the students affects their ability to learn a second language. Age that best suited (optimum age hypothesis) in language learning is time to learn to be successful in the age range is conducive to learning (critical period) and will end in early into adulthood. Fertility (pre-puberty) and must occur before the development is complete on the part of the brain (cerebral lateralization). The brain of a child before puberty flexibility (plasticity of the brain), the children will learn that one then. To learn a second language, but only when fully developed brain. Learning and using a second language fluently, it will be more difficult. Children begin to learn a second language when younger students may not be as good as children who start school at the age of older. There may be other factors that affects learning a second language as well such the ability to learn the first language before starting the second language.