Krashen 提唱の5つの仮説                           wikipediaを参考にしました。
 
1the Aquisition-Learning Hypothesis      there is a strict separation between acquisition and learning
       「習うより慣れろ」か、「慣れるより習え」か。さー、どっちでしょう?
 
2the Monitor Hypothesis      consciously learned language can only be used to monitor language output; it can never be the source of spontaneous speech.
 
3the Natural order Hypothesis  language is acquired in a particular order, and that this order does not change between learners, and is not affected by explicit instruction.
 
4the Input Hypothesis  This states that learners progress in their knowledge of the language when they comprehend language input that is slightly more advanced than their current level. Krashen called this level of input "i+1", where "i" is the language input and "+1" is the next stage of language acquisition.
 
5the Affective Filter Hypothesis  The affective filter is an impediment to learning or acquisition caused by negative emotional ("affective") responses to one's environment.

Corollaries of the input hypothesis
 Talking (output) is not practicing
 Krashen stresses yet again that speaking in the target language does not result in language acquisition.
 Although speaking can indirectly assist in language acquisition, the ability to speak is not the cause of language learning or acquisition. Instead, comprehensible output is the result of language acquisition.

A number of researchers see "comprehensible input" as a major causative factor in second language aquisition.
この点についてはみなさん、意見は一致しているようですね。

こんなことも言ってるようです。
Learning a language, on the other hand, is a conscious process, much like what one experiences in school. New knowledge or language forms are represented consciously in the learner's mind, frequently in the form of language "rules" and "grammar", and the process often involves error correction.
Language learning involves formal instruction and, according to Krashen, is less effective than acquisition.
 
この点についてはみなさん、意見は一致していませんね、きっと。
 
仮説  一定の現象を統一的に説明しうるように設けた仮定。ここから理論的に導きだした結果が実験などで検証されると、仮説の域を脱して一定の限界内で妥当する真理となる。(広辞苑より)
 
hypothesis = temporary prediction that can be tested about how a scientific investigation or experiment will turn out.
 
これでいくとhypothesisは日本語では「一定の限界内で妥当する真理」 なのかな?