克拉申二语习得五假说

Krashen's five hypothesis

——Krashen's Monitor Theory

Five basic hypotheses:

1) The Acquisition-Learning Hypothesis

Acquisition: naturally, subconscious,

informal,

Learning: consciously, formal, 'know about the second language, analysis and correction of errors formally and explicitly addressed.

Krashen supports this claim as follows:

(i) there can be acquisition without learning.

Competent language learners may

speak the language without consciously

knowing the rules.

(ii) there are cases where people can 'know' a rule but do not use it in normal

interaction.

(iii) in any case, nobody knows all the rules of a language. Grammatical explanations even in languages as widely studied as English do not cover the largely unconsciously knowledge of a native-speaker. It often takes linguists years to describe rules which are relatively easily acquired (Ellis 1985).

Acquisition and Learning are not defined by 'where' a second language occurs. Formal learning in the street. The distinction is a central idea in education theory: between deductive (推理:from general to particular) and inductive (归纳)approaches; classroom and naturalistic learning; formal and informal language learning.

2) The Natural Order Hypothesis

Grammatical structures are acquired in a predictable order for both children and adults, irrespective of the language being learnt. Some rules tend to come early and others late. The order does not appear to be determined solely by formal simplicity and there is evidence that it is independent of the order in which rules are taught in language classes.

When a learner engages in natural communication, then the standard order will occur.

3) The Monitor Hypothesis

The Monitor is an editing device that may operate before language performance. Utterances may be modified by being acted upon by the Monitor of learnt knowledge. Such editing may occur before the natural output of speech; it may occur after the output via a correctingdevice. Krashen suggests that monitoring occurs when there is sufficient time, when there is pressure to communicate correctly and not just convey meaning, and when the appropriate rules of speech are known.

Put it the other way:

1) there must be time for a speaker to use

conscious rules effectively. Normal

conversation does not allow for this

monitoring.

2) time alone is not enough. The speaker's attention must also be focused on Form.

3) the speaker must know the rule before the monitor can be used.

Examples include knowing the correct tense to use, when to use the third or first person and rules about plurals. This hypothesis has been criticized for being untestable and for a lack of supportive research evidence.

4) The Input Hypothesis

To explain how language acquisition occurs, Krashen proposes that when learners are exposed to grammatical features a little beyond their current level, those features are 'acquired'. Krashen emphasizes that 'acquisition' is the result of comprehensible language input and not of language production. Input is made

comprehensible because of the help provided by the context. If the language student receives understandable input, language structures will be, according to Krashen, naturally acquired. For Krashen, the ability to communicate in a second language 'emerges' rather than is directly put in place by teaching. Second language

is said to be caused by the process of understanding second language input.

Krashen lists a number of lines of evidence to support the input hypothesis:

⊙ the silent period: this is based on the fact that children in an L2 situation sometimes remain silent for several weeks. Similarly, young children are exposed to their mother tongue (and obviously understand it) before they begin to speak.

⊙ age difference: younger learners may get more comprehensible input because they tend to engage in 'here-and-now' interactions. Older learners may make faster progress initially, however, because they are exposed to more comprehensible input thanks to their broader world knowledge and because of the communicative strategies they have already developed in their L1. ⊙the effect of exposure: the more learners are exposed to comprehensible input, the more their language proficiency develops. Learners who do not have access to comprehensible input are held up in their development.

⊙immersion, bilingual and sheltered language teaching: students in these programs learn effectively because they receive comprehensible input where the focus is on the subject matter being taught rather than the form of the language.

⊙ simple codes (care taker speech, motherese, foreigner talk, etc.) provide ideal input because (a) they are used to communicate meaning, not form, (b) they are roughly tuned to the learners' current level of linguistic competence, and they follow the 'here-and-now' principle which helps the learners understand.

⊙the effects of instruction: instruction is helpful when it is the primary source of comprehensible input. Formal instruction is only helpful because it is source of comprehensible input. Methods that focus on comprehensible input are assumed to be superior to grammar-based or drill-based methods which focus on learning

Input is language which a learner hears or receives and from which he/she can learn. Intake is input which is actually integrated into the learner's interlanguage.

'speakers acquire language in only one way –by understanding messages, or by receiving 'comprehensible (or better still comprehended) input'… We move from i, our current level, to i + 1, the next level along the natural order, by understanding input containing i +1'.

5) The Affective Filter Hypothesis

An affective filter was proposed by Dulay & Burt (1977) with the idea that there is a filter that determines how much a person learns in a formal orinformal language setting. The filter