Instructed Interlanguage Development

Several theorists have claimed that interlanguage (IL) development in instructed (classroom) learners does not differ significantly from that in learners acquiring a second language (SL) naturalistically. The processses and/or sequences in SL development are held to be the same in both acquisitional contexts. Accordingly, some writers on language teaching have advocated provision of "natural" language learning experiences for classroom learners, and the elimination of structural grading, a focus on form and error correction, even for adults. This paper examines the evidence offered in support of the claims concerning instructed IL development. Some recent studies are summarized which illustrate the potential of formal instruction in four areas: (1) acquisition processes, (2) acquisition sequences, (3) rate of acquisition, and (4) level of ultimate SLA attainment. The conclusion is that the claimed similarities between instructed and naturalistic SL acquisition are based on insufficient and weak evidence, that instruction affects learning positively in three of the above four areas, and that the prescriptions for language teaching, therefore, are certainly premature and probably wrong.