Doctor
Alex Rodrigo de Oliveira Faria "Brain Development and Learning a Second Language" (2005) by Ken Pakenham tells us about the adult process of learn a second language and becoming fluent or achieve the level of a native. Pakenham states that a student can develop his or her skills in grammar and vocabulary to become close to a native, but in phonology it is unusual. Pakenhan mentions, in the other hand, that several studies demonstrate that children with age lower than, on average, twelve-years-old have less change to speak with foreign accent when they learn a second language. The scientists uses the critical period theory to explain those capacity and also introduce the concept of cerebral lateralization, process in the brain that made the hemispheres specialize in particular functions. The critical period theory is supported by studies with patients suffering from aphasia, loss of language abilities result of brain damage. Thus, according to the critical theory the left hemisphere of the brain is responsible for the language, for instance, patient with damage in this hemisphere can not communicate well. There is another study made by Lemberge(1967) that showed evidences of the phenomenon of cerebral lateralization, it was observed that children have a flexibility in their brain, so they can use both hemisphere to learn a new language. Putting all this information together the scientists can conclude that the lack of this flexibility is the cause of adults not achieve a native pronunciation. However, the critical period theory is not the absolute truth, some people can have a excellent pronunciation acquired by hard work and