From: https://www.sk.com.br/sk-krash-english.htm
Stephen Krashen’s Principles and Practice in English Language Acquisition can be read and downloaded here: http://www.sdkrashen.com/content/books/principles_and_practice.pdf
“Krashen’s theory of second language acquisition consists of five main hypotheses:
- the Acquisition-Learning hypothesis;
- the Monitor hypothesis;
- the Input hypothesis;
- and the Affective Filter hypothesis;
- the Natural Order hypothesis.
The Input hypothesis is Krashen’s attempt to explain how the learner acquires a second language – how second language acquisition takes place.
The Input hypothesis is only concerned with ‘acquisition’, not ‘learning’.
According to this hypothesis, the learner improves and progresses along the ‘natural order’ when he/she receives second language ‘input’ that is one step beyond his/her current stage of linguistic competence. For example, if a learner is at a stage ‘i’, then acquisition takes place when he/she is exposed to ‘Comprehensible Input’ that belongs to level ‘i + 1’.
Since not all of the learners can be at the same level of linguistic competence at the same time, Krashen suggests that natural communicative input is the key to designing a syllabus, ensuring in this way that each learner will receive some ‘i + 1’ input that is appropriate for his/her current stage of linguistic competence.”
This hypothesis states that learners need to receive input that is just beyond current understanding in order to grow. A little hard, and a little newer to the student. i + 1 means input plus new information.
The basic concepts of Stephen Krashen’s input hypothesis can be summarized as follows:
- The input hypothesis relates to not learning, but acquisition.
- We acquire language by attempting to learn beyond our current level of competence (i + 1).
- Communication is successful when the input is understood and there is enough of it, at which point i + 1 will be provided automatically.