The Social Interactionist theory, as applied to language acquisition, is a concept supported by Brunner and to Skinner in the aspect of placing more importance in the absorption of the target language through consistent communication with native speakers. To Skinner, this theory does not understate any other cognitive theory of language learning, but he places importance on it as a behaviorist who believes that language development is the same in 1st and 2nd language: you learn to speak by speaking. Brunner would agree with this theory because he moves away from formal or monitor language and, instead, focuses on pragmatics which entails the sense,the deep understanding, and the "personality" of the language as it is.
The Nativist perspective of language acquisition states that language learning and acquisition is an innate process that begins in the brain. Interaction simply triggers this natural skill. The leading proponent of nativism is Noam Chomsky, who argues that there is a linguistic corpus within the human brain which he calls the Language Acquisition Device. This corpus is responsible for innate language development. Interaction is what puts the language into context.
The Learning Perspective is what we have today in place, where people learn an L2 through both direct instruction, indirect instruction, and socialization. As a main proponent, Albert Bandura's Social Learning theory states that the process of language acquisition is a combination of cognitive and behavioral processes. However, socialization is imperative because all the innate elements of language are acquired when we imitate others. Therefore, it is safe to correlate that mimicry and learning are closely interconnected as far as language goes.
There is not an official perspective of language learning that has been universally accepted as "the" one. As the field of neurolinguistics continues to grow, scientists gather more information about the neurological processes that lead to language learning. Moreover, through empirical research and standardized test results, we can shape the strategies of L2 teaching to create an optimal learning environment regardless of what perspective we choose to follow.