Krashen claims we can acquire a second language because a) we have access to a Chomskyan Language Acquisition Device, and b) because speakers instinctively provide 'the right stuff' for acquisition in the process of making their language comprehensible. But you may remember that Chomsky's notion of a Language Acquisition Device or Universal Grammar was designed to explain how children acquire language despite the input; simplification may help, but it cannot explain the whole process (see sections 2.2.3.2 and 2.2.3.3). Furthermore, we have seen some evidence which suggests that even if a Language Acquisition Device exists, it may not be available after puberty to support adult second language acquisition (see section 2.2.3.4).

Without the help of a Language Acquisition Device, is acquisition through understanding alone really plausible? First of all, how do we 'understand' language if we haven't yet acquired knowledge of it? Krashen's answer is that we use context and general knowledge of the world to guess at meaning. This seems all very well, but as Skehan (1998: 24-27) points out, Krashen then assumes that by guessing at meaning, we are also able subconsciously to focus on the grammar or 'form' of the language input. In Skehan's view, this is psycholinguistically implausible, at least as far as the full grammatical complexity of the target language is concerned. In using language for communication, he argues, our tendency is to reduce attention to form, not to increase it: thus it seems difficult to imagine that complex grammatical structures could be acquired just from focusing on meaning.

Normal communication is pervaded by the pressures of processing language in real time. We comprehend and produce language not by exhaustively analysing and computing (although we can do these things if we have to, for reasons of creativity or precision), but instead by drawing shamelessly on probabilistic strategies which work effectively enough [...] at considerable speed of processing. […] The central point is that language use, in itself, does not lead to the development of an analytic knowledge system since meaning distracts attention from form. (Skehan, 1998: 27)

Reflective task 17