(2) The monitor hypothesis
The language that one has subconsciously acquired “initiates our utterances in a second language and is responsible for our fluency,” whereas the language that we have consciously learned acts as an editor in situations where the learner has enough time to edit, is focused on form, and knows the rule, such as on a grammar test in a language classroom or when carefully writing a composition. This conscious editor is called the Monitor.
The monitor hypothesis explains the relationship between acquisition and learning and defines the influence of the latter on the former. The monitoring function is the practical result of the learned grammar.
(3) The natural order hypothesis
The natural order hypothesis is based on Krashen’s research findings which suggested that the acquisition of grammatical structures follows a “natural order” which is predictable.
(4) The input hypothesis
The input hypothesis answers the question of how a language acquirer develops competency over time. It states that a language acquirer who at “level i” must receive comprehensible input that is at “level i+1.” We acquire, in other words, only when we understand language that contains structure that is “a little beyond” where we are now.
The input hypothesis is the result of Krashen’s attempt to explain how the learner acquires a second language. In other words, this hypothesis is Krashen’s explanation of how second language acquisition takes place.
(5) The affective filter hypothesis
Motivation, self-confidence, and anxiety al本文来自辣*文~论^文'网l affect language acquisition, in effect raising or lowering the “stickiness” or “penetration” of any comprehensible input that is received
The affective filter hypothesis embodies Krashen’s view that a number of “affective variables” play a facilitative, but non-causal, role in second language acquisition. Theses variables include motivation, self-confidence and anxiety.
1.1.1 An Overview of Input
Input is probably one of the most important concepts in SLA. The relation between input and SLA is always a key aspect in the field of SLA. Input, itself, includes all the language signals, i.e. words, phrases and sentences of one particular language, and signals from other language that may be brought in through translation, comparison and so on. In language learning it means the linguistic material to which the learner is exposed, i.e. the learner’s experience of the target language in all its manifestations (Sharwood Smith, 1993). In the classroom teaching, the effect of linguistic input is closely connected with the strategy for its transmission to the students. It seems to be a direct and informative signal which conveys semantic sense (Andersen, 1981; Larsen-Freeman, 1991; Nunan, 1995). In language acquisition, input plays an indispensable role. However, the role of input in language acquisition is always a controversial question. Behaviorists and Mentalists differ greatly on it.
1.1.2 The Limitations of Input Hypothesis
We should also point out that there are many limitations to the Input Hypothesis theory. First, Krashen emphasizes the importance of input in language acq毕业论文http://www.751com.cn uisition, but the definition of input is narrow, as he advocates natural input while neglecting non-natural input, this is impossible for Chinese learners of English to be in the real situation of communication. What’s more, Krashen emphasizes much more on the input than output; this will impede students’ communicative ability. Krashen theory also neglects the role of learners themselves, without positive motivation and attitude of learning foreign language; the input alone would not be enough for SLA.