Explain how input, central processing and output work to process information in L2 acquisition/learning.

Input, central processing and output are three components of a cognitive model of second/foreign language learning. The cognitive model has been raised by the “cognitivists” (researchers who use cognitive models to study second/foreign language learning) believing that psycholinguistic perspectives have been underrepresented due to the influence of structured linguistics and chomskian theories.
I’d like to discuss how this model works to process information in L2 acquisition one by one.
“Input provides essential positive evidence, the language data that allows acquisition to occur.” In a simpler sense, input is what the educators feed the students. They are the grammar or language lessons taught by the teacher within the four walls. The effectivity of an input depends on the approach the teacher uses and how she handles such approaches to meet the needs of her students. To quote Grass (1997), second language is shaped by input one receives. Thus, a teacher’s role in facilitating learning matters very much. In the input stage, it is important that students are able to “notice” structures because they do not process all of the input they constantly receive but only select.
Moreover, Information Processing refers to the many complex mental transformation which occurs after input. There are two basic psychological concepts used to understand language input : bottom-up which is the process of decoding specific bits and top-down which refers to the use of world knowledge and past experiences. It is quite obvious that top-down processing is the concept suited for language learning wherein students are able to understand the totality of whatever communicative input is given to them “with out needing to understand all of the grammar forms or vocabulary” which is the reason why they fail without having someone to discuss on form. Hence, going back to input, students need to notice and be aware of what they are learning; for that matter teacher need to regularly backslide to previous lessons as they connect them to other lessons.
If someone gives an input there’s always an output awaiting. Output serves critical functions in the language process. This is where assessment comes in, in the form of games, drills and/or tests. From these assessment procedures, we can determine which part the student did not understand well. Because the students might understand the general meaning of what is being fed to them using the top-down process but they might not fully understand the grammar or vocabulary. In this output follows corrective feed back from the teacher as well as peers explaining the correct form used ,such error correction provide negative evidence thereby facilitating learners’ noticing of the correct form which encourage the child to correct his/ her errors and build their own correct communicative constructs.