If
i represents previously acquired linguistic competence and extra-linguistic knowledge, the hypothesis claims that we move from
i to
i+1 by understanding input that contains
i+1. Extra-linguistic knowledge includes our knowledge of the world and of the situation, that is, the
context. The
+1 represents 'the next increment' of new knowledge or language structure that will be within the learner's capacity to acquire. 'Comprehensible input' is the crucial and necessary ingredient for the acquisition of language. The comprehensible input hypothesis can be restated in terms of the
natural order hypothesis. For example, if we acquire the
rules of language in a linear order (1, 2, 3...), then
i represents the last rule or language form learned, and
i+1 is the next structure that should be learned. It must be stressed, however, that just any input is not sufficient; the input received must be comprehensible. •
When enough comprehensible input is provided, i+1
is present.If language models and teachers provide enough comprehensible input, then the structures that acquirers are ready to learn will be present in that input. According to Krashen, this is a better method of developing grammatical accuracy than direct grammar teaching. •
The teaching order is not based on the natural order.Instead, students will acquire the language in a natural order by receiving comprehensible input. == Acquisition-learning hypothesis ==