' (Gass, 2013) .
The aim of this study is to explain the second language acquisition, the theories of the second language learning briefly. The basic aim of this study is to introduce the stages of second language acquisition by comparing them with the stages of first language acquisition briefly.
Second Language Acquisition.
Language acquisition has been a major topic of research of linguists for the centuries. It can be seen different theories and ideas that I will mention in this study about language learning which one is belong to Noam Chomsky and the other one is belong to Stephen Krashen. According to Chomsky's theory, human brain is ready to acquire language at specific stages in the developmental process. Chomsky indicates that language learning is innate activity because we are born with the capacity for language. On the other hand, Krashen gives five hypotheses for second language acquisition with the following:.
the Acquisition-Learning hypothesis,.
the Monitor hypothesis,.
the Input hypothesis,.
the Natural Order hypothesis,.
the Affective Filter hypothesis. (Krashen, 1982. pp, 10-30) .
According to Krashen, the acquisition-learning hypothesis is the most important of all hypotheses that he consists of because there are two systems for second language performance which are 'the acquired system' that focus on subconscious process similar with children first year language acquirement and 'the learned system' that focus on conscious process of language learning and error correction by others. He also believes that acquisition is important than learning. When it is looked at deeper his study, it can be seen that ' 'children acquire, while adults can only learn.'' (Krashen, 1982. pp. 10).
When we look at the history pages of second language learning studies, in 1950-60s, there are some studies who give descriptions and theories about how second language learned. In the theory of behaviorism, for example, ' 'language learning is seen like any other kind of learning, as the formation of habits''.
