In my thesis, I will touch upon the logical problem of foreign language learning, as well as the problems of observation in child language research as these problems cannot be left out when one learns a second language or one observes others who are learning languages. The focus of my thesis will be the optimal age for learning a second language. I believe that if it is possible to introduce a second language at an early age it should be done, as research has found, that the young child is not only biologically more receptive to learning a second language but I believe the child also has the necessary cognitive basis with which he or she can rapidly learn the language and besides these, the affective advantage that is the anxiety-free and unconscious emotional state of a child should be exploited, too. The plasticity of the brain changes as the child matures changing the way one can learn a second language and the influence of the education and social environment bring about transformations that are irreversible and causes radical/profound changes. Those early years provide an opportunity for learning a second language effortlessly and it cannot be ignored that considerable amount of time is given for young children who can pick up the language relatively easily compared with adult language learners.