Krashen proposes five hypothesis about the second language acquisition process.
1.- The Acquisiton -Learning distinction
According to him, there are two independent ways of developing competence in a second language
a) Acquisiton: It is a subconscious process; "Picking up a language"
b)Learning: It is a conscious knowledge; "knowing about the language, rules".
He hasthe idea that adults also can acquire a language because the ability to pick up a language does not dissappear at puberty". He also thinks that both process (Learning and Acquition) can take place in a natural setting.
2.- The natural order Hypothesis:
He claimes that the acquisition of grammar takes place in a predictable order (listening, speaking, writing, reading). According to a study, different groups of second language acquirers showed striking similarities, that's way he support that the natural order happens in every language
3.- The monitor Hypothesis:
it posots that acquisiton and learning are used in vary specific ways. Acquisition initiates utterances in second language and is responsable for our fluency, then learning has one function only: As a monitor or editor.
There are three types of monitor users:
a) Monitor overusers: These users tend to use a lot their monitor. Because of that they tends to speak slowly.
b) Monitor underusers: These users do not use their monitor as they should. Because of that they speak with a lot of errors.
c)Optimal users: These user use their monitor as they should.
4.-The input hypothesis:
He claimed that we acquire by going for meaning first ans as a result we acquire structure. In order to that being possible we need comprehensible input. That means that we have to understand what we hear.
This theory says that the teacher has to speak in a level beyond the student's.Because if the teacher speakes in the same level that the student then te student will not learn that much.
5.- The Affective Filter Hypothesis:
It postulates that those acquirers with optimal attitudes will seek more input. that input will help to activate their Language Acquisiti on Device. Those with poor attitudes will seek less input
