时间：2022-09-08 09:58:11
Abstract：In the 1980s，Krashen came up with a kind of Second Language Acquisition（SLA）theory which has a far-reaching effect on English Teaching，namely Input Hypothesis.It states simply that we acquire language by understanding input that is a little beyond our current level of competence.The author discovers the fact that the Input Hypothesis plays an extremely important role in guiding Reading Instruction through the in-depth analysis of the theory，which can be used to tackle the issues of inappropriately-chosen reading materials and monotonous teaching method.Therefore，the paper attempts to solve the problems existing in Reading Instruction and obtain some enlightenments under the guidance of Input Hypothesis.
Key words：Krashens Input Hypothesis；Reading Instruction
1.Instruction
It is generally accepted that Reading is an indispensable and significant part of English Learning.Since Reading is not only the channel of obtaining language knowledge，grammatical rules and information，but also the window of learning the culture of the target language community.However，English teachers come across quite a few pressing problems which they are not able to solve even with great efforts.For instance，many English teachers find it difficult to grasp the degree of difficulty when it comes to selecting reading materials.If the selected materials are too easy for learners，it will be difficult to stimulate learners interest；if too difficult，learners will not comprehend.Thus，English teachers have been paying close attention to solving such problems.In the following part，the author firstly illustrates the main ideas of Krashens Input Hypothesis and then points out the enlightenments on Reading Instruction.
2.The Main Ideas of Krashens Input Hypothesis Theory
1）The“i+1”Principle of Language Input
Krashen claims that it is not a good thing for learners if the input materials are too easy，owing to the fact that learners are fond of doing something challenging，so easy materials cannot attract their attention，instead，they will put learners into a state of sluggish.In addition，Krashen advocates that learners need comprehensible input and appropriately enhance the difficulty of input materials under the premise of comprehensibility.Besides，Krashen defines learners present cognitive level as“i”，and the next and higher development stage as“i+1”.Meanwhile，he points out that only when most of the content of the input materials are in compliance with the learners present cognitive level and the minority are beyond the cognitive scope are able to facilitate the development of learners language and finally acquire the language.
2）Roughly Tuned Input and Finely Tuned Input
Krashen points out that there exist two forms of input：roughly tuned input and finely-tuned input.The former provides students with extensive learning materials，and serves as a net spreading out around the current level of acquisition of the learner.In this case，“i”also consist of instances of“i+1”，and it is said that“when communication is successful，when the input is understood and there is enough of it，i+1 will be provided automatically”（Krashen 1982：22）.For instance，caretaker speech belongs to roughly tuned input，as it is much simpler in structure and form，seems to be roughly tuned to the linguistic level of the child and it becomes more and more complicated as the child grows in linguistical maturity.while the latter，finely tuned input，exposes students to finely-selected learning materials and focuses on the the learners present level of acquisition，targeting at one structure at one time.One of the typical examples of finely tuned input is teaching syllabus，whose goal is‘i+1’，so the objective of the teaching and learning is to teach and learn a specifical grammatical item or sentence structure.
Krashen argues that roughly tuned input is of much more significance and advantages than finely tuned input.“Roughly tuned input will be good for more than one acquirer at a time，even when they are at slightly different levels.Finally，roughly tuned caretaker speech in the form of teacher talk or or foreign talk，will nearly always be more interesting than exercise that focuses just on one grammatical point”（Krashen and Terrell 1983：35）.
3）The Silent Period
Krashen comes up with the concept of the silent period which is a period of time when a learner grows in his or her linguistical competence，and via obtaining sufficient comprehensible input，begin speaking so as to support his hypothesis.McLaughlin（1987），however，argues that the silent period cannot be a convincing evidence to demonstrate how the language is acquired.The learners anxiety or introvert personality can also result in the silent period，and there may exist other factors contributing to the phenomenon of the silent period.McLaughlin further claims that it is impossible for the learner to interpret the input which includes words and structures that he or she has not been familiar with yet.While Krashen argues that learners can understand the learning materials containing”i+1”with the help of extra linguistical information，context，etc.
4）Characteristics of Optimal Input
According to Krashen（1985），optimal input should possess the following four characteristics：
①Comprehensible
Comprehensible input is the prerequisite for the acquisition of language，since it is just like a sort of noise for language acquirers to get the incomprehensible input.
②Both Interesting and Relevant
It is necessary to process the meaning of input materials in order to facilitate the acquisition of language.As Krashen points out，the more interesting and relevant the input is，the more likely learner will acquire language unconsciously.
③Not Grammatically Sequenced
Krashen believes that that it is not advisable to sequence teaching materials in grammatical order，if the teaching objective is“acquire”instead of“learn”.
④ Sufficient Input
In order to acquire new language structures，it is essential for learners to keep reading all kinds of materials in the target language and take every opportunity to get sufficient input.They should do whatever they can to expose themselves to the language they are learning.
3.The Enlightenments of Input Hypothesis on Reading Instruction
Through the analysis of Krashens input hypothesis，the author finds out that the theory plays an important role in guiding reading instruction.It gives educators the following enlightenments to improve teaching strategies：
3.1 Observing the“i+1”Principle
According to“i+1”principle，the difficulty of input materials should be in compliance with the learners current level as a whole，but it allows a little section of the input to slightly excel his or her present level.In this way，learners can improve their skills of using target language through analyzing the materials containing“i+1”.
Therefore，English teachers should get acquaintance of students current level and select proper reading materials containing“i+1”when teaching reading comprehension.An excellent English teacher has the ability to provide students with comprehensible and meaningful reading materials with moderate difficulty.For instance，experienced teachers will select simplified novel，fairy tale and other materials with low difficulty for beginners；and provide academic and original materials for advanced students.Teachers should be encouraged to adjust the difficulty of reading materials according to students feedback.
3.2 Providing Students with Interesting and Relevant Reading Materials
Krashen claims that it is more important for learners to understand the meaning than the form of language input.So the selected reading materials needs to be interesting and have relationship with students daily life.Only in this way can students interests and motives be stimulated，which is contributable for students to interpreting the meaning of materials.In addition，interesting and relevant materials can also help students to reduce or even eliminate psychological burdens，such as anxiety which often occurs when reading，so that students can read in a relaxing environment without any distraction.Krashen（1985）believes that in a relaxing environment the full use of the optimal input will enable acquisition to take place at a much quicker speed.
3.3 Using Context and Extra-linguistic Information to Help Learners Understand the Materials
Krashen（1985）argues that learners are able to make use of context and extra-linguistic information to understand the materials a little bit beyond the learners present level.Thus，English teachers should utilize all sorts of reading skills and methods to help students understand materials.
3.3.1 Analyzing Reading Materials through Context
Experienced English learners often make use of context when they do not know the words or structures in reading comprehension.While beginners put their focuses only on understanding the literal meaning of reading materials，they do not have the awareness of seeing the reading materials from a holistic perspective.They tend to ignore the logical relationship among lines.Therefore，English teachers are supposed to help students to foster awareness of context and teach them how to apply the context method in reading comprehension，and eventually make students sensitive to context.
3.3.2 Using Extra-linguistic Information to Analyze Reading Materials
Nuttall（1982：37）holds the view that teachers should make use of extra-linguistic information to help students understand reading materials such as punctuation，diagram，icon etc.Besides，English teachers should attach great importance to the culture of English language community which also belongs to extra-linguistic information.It is said that foreign language acquisition is a process of interaction with another culture.As a part of culture，language is a reflection of culture，but meanwhile，it is also influenced by culture.Thus，it is very essential for learners to get sufficient input about the culture of English language community and know exactly the cultural difference between China and Western countries.Moreover，English teachers should introduce the background knowledge and culture behind the reading materials before students start to read.
3.4 Exposing Learners to Sufficient Roughly-tuned Reading Materials
Krashen claims that learners will automatically acquire the linguistical knowledge containing“i+1”when they are exposed to sufficient roughly tuned input.Besides，he points out that finely-tuned materials are only suitable for the minority of learners，since most of the learners are at different levels，while roughly-tuned input can be in compliance with the level of most learners.Therefore，English teachers should provide students with abundant reading materials which can meet the needs of students at various levels.
3.5 Allowing Students to Have the Silent Period
Krashen believes that learners have to go through the process of intake and then digestion，which is the silent period.So students should be allowed a period of time to digest and process the input reading materials which is an accumulating process.What the teachers should do is to prevent any distraction and wait for the huge leap in reading comprehension of students with patience during the silent period.
4.Conclusion
The paper introduces the main ideas of Krashens input hypothesis in the first section，and then in the following sections，the author puts forward some beneficial enlightenments of input hypothesis theory on reading instruction.According to the theory，English teachers should select the comprehensible，interesting，relevant and roughly-tuned reading materials for students when teaching reading comprehension.Besides，students should be allowed to have the silent period to digest the input.In addition，it is also of great importance for teachers to help students learn how to analyze complicated reading materials through context and extra-linguistic information.
Biography
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