Input hypothesis

The input hypothesis, also known as the monitor model, is a group of five hypotheses of second-language acquisition developed by the linguist Stephen Krashen in the 1970s and 1980s.

[1][2] The hypotheses put primary importance on the comprehensible input (CI) that language learners are exposed to.

Krashen's hypotheses have been influential in language education, particularly in the United States, but have received criticism from some academics.

Two of the main criticisms state that the hypotheses are untestable, and that they assume a degree of separation between acquisition and learning that has not been proven to exist.

The five hypotheses that Krashen proposed are as follows: If i represents previously acquired linguistic competence and extra-linguistic knowledge, the hypothesis claims that we move from i to i+1 by understanding input that contains i+1.

According to Stephen Krashen's acquisition-learning hypothesis, there are two independent ways in which we develop our linguistic skills: acquisition and learning.

According to the affective filter hypothesis, certain emotions, such as anxiety, self-doubt, and mere boredom interfere with the process of acquiring a second language.

[3] The hypothesis further states that the blockage can be reduced by sparking interest, providing low-anxiety environments, and bolstering the learner's self-esteem.

One is allowing for a silent period (not expecting the student to speak before they have received an adequate amount of comprehensible input according to their individual needs).

A teacher needs to be aware of the student's home life, as this domain is the biggest contributor to the affective filter.

According to Wolfgang Butzkamm & John A. W. Caldwell (2009), comprehensible input, defined by Krashen as understanding messages, is indeed the necessary condition for acquisition, but it is not sufficient.

They must not only understand what is meant but also how things are quite literally expressed, i.e. how the different meaning components are put together to produce the message.

Only now is understanding complete, and we come into full possession of the phrase which can become a recipe for many more sentences, such as "Wie alt ist es?"

The theory underlies Krashen and Terrell's comprehension-based language learning methodology known as the natural approach (1983).