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Input Hypothesis Specifications | TESL Lessons

Published on March 22nd, 2017 | Last updated on November 26th, 2019 by | Category: TESOL / TESL Issues through CALL | No Comments on Input Hypothesis Specifications | TESL Lessons | 84 Views | Reading Time: 2 minutes

Input Hypothesis

Input Hypothesis

Krashen’s Input Hypothesis explicitly rejects a role for consciousness, claiming that “acquisition” is a subconscious process.

Krashen assumed a ‘language acquisition device’, that is, an innate mental structure capable of handling both first and second language acquisition. The input activates this innate structure. But only input of a very specific kind (i + 1) will be useful in altering a learner’s grammar.

Krashen (1981, 1982) distinguished between acquisition and learning. The former is an implicit, subconscious process and is reflected in the natural order of acquisition. The latter is an explicit, conscious process and results in metalinguistic knowledge. The Input Hypothesis (Krashen, 1985, 1994) relates only to acquisition. It makes the following claims:

  1. Learners progress along the natural order by understanding input that contains structures a little bit beyond their current level of competence (i + 1).
  2. Although comprehensible input is necessary for acquisition to take place, it is not sufficient, as learners also need to be affectively disposed to ‘let in’ the input they comprehend.
  3. Input becomes comprehensible as a result of simplification and with the help of contextual and extralinguistic clues.
  4. Speaking is the result of acquisition, not its cause. Learner production does not contribute directly to acquisition.
  5. If input is understood, and there is enough of it, the necessary grammar is automatically provided.
  6. The teacher’s main role, then, is to ensure that students receive comprehensible input.

It claims that acquisition occurs through processing ‘comprehensible input’ in which forms occur from the learner’s next natural developmental stage.

It was proposed by Krashen.


  • The hypothesis itself is not specific as to how to define levels of knowledge (Gass & Selinker, 2008).
  • Krashen states that there has to be sufficient quantity of the appropriate input. But what is sufficient quantity? How do we know whether the quantity is sufficient or not (Gass & Selinker, 2008)?
  • How does extralinguistic information aid in actual acquisition or internalisation of a linguistic rule, if by ‘understanding’ Krashen meant understanding at the level of meaning?

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