Various theories are put forward to describe second language acquisition (SLA). The following theories represent serious thinking over the past century about the way a person acquires or learns a second language.
The first theory will be Behaviourism. In mid-century, Burrhus Frederic Skinner developed behaviourist theory which predicted that any human behaviour could be learned through a process of stimulus, response, and positive or negative reinforcement (S-R-R). This S-R-R process is to make the desired behaviour become a habit that can be performed spontaneously. According to behaviourists, this process also can be applied into language learning. A concrete example of behaviourism applied directly to higher-level training, as a result of Bandura’ (1977) work, is behaviour. The terms are used interchangeably. This uses techniques such as "goal setting" and "self-reinforcement" to help people acquire the characteristics of a competent role model.
Next, the second theory will be Language Acquisition Device (LAD) which developed by Noam Chomsky. Chomsky found out that there is an innate ability in every people which enable them to acquire and use language and this ability is known as LAD. Chomsky was not as concerned with the actual language being spoken as with the unspoken but understood rules that made the utterances appropriate, correct to native speakers. He argued that the stages of development that are required for children to develop their cognitive abilities in other areas do not apply to learning language.
Then, the third theory is Interaction Hypothesis theory which introduced by Long in 1983 which is about the role of interaction in the second language learning and more concerned with how input is made comprehensible. According to this theory, the modified input created within interaction can be facilitating in explaining linguistic forms that