1、LOGOLOGOPage 2Five Hypothesesn Acquisition-Learning Hypothesisn Monitor Hypothesisn Natural Order Hypothesisn Input Hypothesisn Affective Filter HypothesisLOGOPage 3Acquisition-Learning Hypothesisn Krashen claimed that adult second language learners have two means for internalizing the target langua

2、ge. The firsst is acquisition a subconscious and intuitive process of constructing the system of a language. the second means is a conscious learning process in which learners attend to form, figure out rules, and are generally aware of their own process. According to him,fluency in second language

3、preformance is due to what we have acquired, not what we have learned.(1981,P.99)LOGOPage 4Monitor Hypothesisn The monitor is involved in learning,not in acquisition. It is a device for watchdogging ones output, for editing and making alterations or corrections as they are consciously perceived.Such

4、 explicit and intentional learning, according to Krashen, ought to be largely avoided, as it presumed to hinder acquisition. Only once fluency is established should an optimal amount of monitoring, or editing, be employed by the learner.(Krashen,1981)LOGOPage 5Natural Order Hypothesisn Following the

5、 earlier morpheme order studies of Dulay and Burt(1974b,1976) and others, Krashen has claimed that we acquire language rules in a predictable or natural order.LOGOPage 6Input Hypothesisn According to Krashen(1984,P.61), comprhensible input is the only true cause of second language acquisition. the I

6、nput Hypothesis claims that an important condition for language acquisition to occur is that the acquirer understand(via hearing or reading) input language that contains structure a bit beyond his or her current level of competence.If an acquirer is at stage or level i, the input he or she understan

7、ds should contain i+1. In ther words, the language that learners are exposed to should be just far enough beyond their current competence that they can understand most of it but still be challenged to make progress.LOGOPage 7Affective Filter Hypothesisn Krashen has further claimed that the best acqu

8、isition will occur in environments where anxiety is low and defensiveness absent, or, in Krashens terms, in contexts where the affective filter is low.LOGOPage 8Evaluations of the Five Hypothesesn McLaughlin(1990a,1978) sharply criticized Krashens rather fuzzy distinction between subconscious (acqui

9、sition) and conscious (learning) processes.n A second criticism of Krashens views arose out of the claim that there is no interface-no overlap-between acquisition and learning.n Krashen presents the i+1 formula as if we are actually able to define i and 1, but we are not. Krashens i+1 also closely a

10、pproximates Vygotskys ZPD,the metaphorical space between a learners current level of development and the next level.n A fourth, and perhaps the most crucial, difficulty in Krashens Input Hypothesis is found in his explicit claim(1986,p.62) that comprehensible input is the only causative variable in second language acquisition. In other words,