Stephen Krashen draws a big distinction between learnt and acquired language, a distinction that has caused controversy in itself, quite apart from his ideas for promoting this acquisition. According to Krashen, students who are taught in a formal, form-focussed way will “learn” the language but never fully acquire it. Acquisition, which is the basis for all L1 knowledge, consists of rules and principles that are not available to conscious attention. By contrast, learnt language can only be used as a “monitor” (a check, as it were) to what we say in L2. Krashen argues this is the only use of learnt language and further goes on to say that learnt knowledge can never become acquired knowledge. Krashen’s model has thus been termed a “dual competence” model.
We now we move onto ways in which Krashen states that this acquisition can be promoted in the un-naturalistic setting of the classroom. The crux of Krashen’s theories is that students acquire (as opposed to learn) when they are able to understand something (primarily through context) that is a little above their current level of understanding. There is no explicit focus on form such as, for example, “present perfect” (which aids only “learning”) but new language is inserted into utterances containing language already known to the students. Krashen calls this “comprehensible input” and McDonough (1995) describes it as an “accretion of knowledge from instances of incomprehension embedded in the comprehensible.”
Krashen talks about a number of ways in which students’ acquisition is made easier. Their “affective filter” should be kept low. This means their reception of input should be kept as high as possible. To this end, Krashen thinks that the students should be as relaxed as possible. Production should not be forced in any way. Students will produce when they are ready to. A high level of error correction is also seen as being bad for keeping the affective filter low. In everyday terms, a student who is too often corrected will eventually elect to just stay quiet.
Error correction, only useful for “learning”, should thus be generally avoided if acquisition is the aim of the teacher. Krashen doesn’t believe the classroom to be the place where a second language can be successfully acquired and so states that the priority in the classroom should be to equip students for real-life conversations and for real-life situations where acquisition is more likely to take place. It should be noted here that Krashen has been heavily criticised for making such a bold distinction between learning and acquisition and especially for his claim that classroom ESL teaching does little or nothing to help students acquire a language.