Comprehensible Input

We acquire language when we receive comprehensible input in a low anxiety situation, that is, when we understand what people say to us and when we understand what we read. This is the core of a general theory of language acquisition, a combination of the Comprehension (a.k.a. Input) Hypothesis and the Affective Filter Hypothesis (for evidence and discussion of current controversies, see Krashen, 2002). We do not, in other words, acquire language by learning about language, by study of the rules and by memorizing vocabulary.

The importance of recreational reading

Free voluntary reading is an extremely powerful form of comprehensible input, and it is delivered in a low-anxiety environment. Those who participate in free reading programs in school make superior gains in reading, vocabulary, grammar, and writing (Krashen, 1993, 2002).

Younger is not faster

Contrary to popular opinion, younger acquirers are not faster at language acquisition. Rather, older children are faster, in the short run, than younger children, and adults are faster than children, In the long run, however, children do better than adults, that is, those who begin second language acquisition as children have the potential of achieving native-like proficiency, but those who begin as adults generally do not (Krashen, Scarcella, and Long, 1978). It should be pointed out, however, that adults, given enough comprehensible input and a reasonably low-anxiety environment, typically achieve very high levels of competence in second languages.

The development of a good accent

It is true that studies of immigrant children show that those who begin second language acquisition before puberty tend to develop native accents and those who start later typically do not. It is also true, however, that many who start later develop excellent accents, very close to native, and many who start foreign languages young do not. For example, "heritage language" speakers, those who speak a minority language at home (e.g. American-born Chinese living in the US) often speak the heritage language with an accent, even though they have been hearing it and speaking it their entire lives. In addition to age, another variable appears to be at work, what Smith (1988) calls "club membership": we acquire the accents of the group we feel we are a member of, or feel we can join. This explains why children do not talk exactly the way their parents talk - they talk the way their friends talk. (Accent may be a result of a reluctance to talk in a certain way, not a lack of competence. For speculation, see Krashen, 2003.)

The role of the first language

Several decades ago, it was thought that the first language actively interfered with second language acquisition, that habits from the first language had to be eliminated or there would be "interference." Research since then is more consistent with the position that the first language does not interfere; rather, we "fall back" on the structures and rules of our first language in the absence of second language competence (Newmark, 1966; Krashen, 1983). Thus, the cure for first language influence is simply more second language acquisition.

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