Learning Japanese as a Second Language: A Processability Perspect ...

CAH was motivated by structural linguistics, which originated with Saussure (Lyons, 1968) and behavioural psychology (Skinner, 1957)—both of which were influential from the 1940s to the 1960s. In linguistics, a corpus-based approach was dominant, and structural linguists provided detailed linguistic descriptions of particular languages from collections of utterances produced by speakers of the language. In psychology, meanwhile, behaviourists put forward the view that it was possible to understand all human phenomena through the study of observable and measurable behaviour. Behaviourists regarded language learning as a part of general learning: L1 learning was understood as the formation of a set of habits through imitation of input and positive reinforcement.

CAH was generated through the meeting of these two approaches in the fields of linguistics and psychology. The logic of CAH is relatively simple: If it is true that L1 acquisition is the formation of a set of habits, then learning an L2 is the process of overcoming the habits which were acquired through L1 learning so that the learner can acquire the new habits specific to the target language. The hypothesis, according to Lado (1957), was as follows:

1. If L1 and L2 are similar, positive transfer occurs and it is easy for the learners to learn L2.

2. If L1 and L2 are different, negative transfer (i.e., interference) occurs and it is difficult for the learners to learn L2, leading to errors and problems for them.

CAH then suggested that it is important to uncover L1–L2 differences through comparison of the two languages—to be achieved by looking at the descriptive work produced by structural linguists on each language. This examination of the differences between L1 and L2 was expected to enable CAH to predict what troublesome areas learners would encounter, and thereby to assist teachers in reducing learners’ errors to a minimum.

Initially, CAH was appealing, as it appeared to make accurate predictions about L1 transfer and thus to provide language teachers with good