Studies On Krashen's Comprehensible Input Hypothesis

Krashen's Input Hypothesis is one of the most important theories in second language acquisition. The theory provides a good theoretical framework for China's foreign language teaching. This paper aims to study Krashen's Comprehensible Input and attempts to discover how to choose optimal teaching methods, which can improve China's foreign language teaching along with China's actual situation and the author's teaching experience. This thesis is composed of six parts.Introduction states that our country needs more and more foreign language talents with the entrance of WTO and our Beijing's successful bid for 2008 Olympic game. Therefore, learning foreign language becomes more and more important. The author believes that in SLA, Krashen's Comprehensible Input takes a decisive effect and the theory is valuable to study. Chapter one introduces the basic ideas of Krashen's second language acquisition theories, the concept of comprehensible input, the development of input hypothesis and Krashen's interpretation of input hypothesis and mainly focuses on the three different views on input in the second language acquisition and criticisms on his input hypothesis. Krashen's second language acquisition theory is a comprehensive one, consisting of five inter-related hypotheses: learning-acquisition hypothesis, natural order hypothesis, monitor hypothesis, input hypothesis and affective-filter hypothesis, with the input hypothesis as the core. Krashen believes that: 1. The input hypothesis relates to acquisition, not learning; 2. We acquire by understanding language that contains structure a bit beyond our current level of competence (i+1); 3. When communication is successful, when the input is understood and there is enough of it, "i+1' will be provided automatically; 4. Production ability emerges. It is not taught directly. In the following, Krashen put forward four essential factors that needed in second language acquisition: 1. Input should be comprehensible; 2. Input should be interesting and/or relevant; 3. Input should not grammatically sequence; 4. Input should be in sufficient quantity. Linguists hold three different views on the role of input in second language acquisition: behaviorist, nativist, and interactionist. Behaviorist accounts of SLA view the learner as 'a language-producing machine'. The linguistic environment is seen as the crucial determining factor. Input is comprised of stimuli and feedback. Nativist accounts of SLA view the learner as 'a grand initiator' or 'black box'. They emphasize the internal factors of language acquisition, i.e. the language acquisition device in our mind. The language input does not play a key role. The interactionist view sees language development as the result both of input factors and of innate mechanisms. Language acquisition derives from the collaborative efforts of the learner and his interlocutors and involves a dynamic interplay between external and internal factors. Linguists criticize the input hypothesis as follows:1. The definition of comprehensible input is indefinite.2. The use of formulaic expression contradicts Krashen's comprehensible input.3. Comprehensible output is no less important than comprehensible input. 4. Comprehensible input can facilitate acquisition but is not a necessary condition of acquisition.Chapter II illustrates the author's own interpretation of comprehensible input. The author believes that: 1. Language is a tool of communication, so it must be comprehensible. Supposed the learner does not understand the message, there will be no acquisition. In other words, incomprehensible input, or "noise", will not help. 2. Comprehensible input can facilitate the students' understanding. The author summarized the following aspects that can aid comprehension:1.) Appropriate rate of speech can aid the learners to understand the input. 2.) Try to use more frequent, neutral and concrete vocabulary, and to avoid idioms and slang, because reducing variation in words can make it easier for t...