Introduction

The long-neglected issue of vocabulary acquisition is currently receiving attention in second language pedagogy and research – reflecting the importance always accorded it by learners. But it is still far from clear how learners acquire vocabulary or how it can best be taught. Reading comprehension processes may offer some clues. There is considerable evidence from first language studies that extensive reading for meaning leads to vocabulary acquisition over time, and indeed that reading probably accounts for most L1 vocabulary expansion beyond the first few thousand words in common oral usage. Second language research on this issue is sparse, but what there is indicates that extensive reading programs are generally more effective than systematic vocabulary instruction using decontextualized exercises (see, for example, Elley and Mangubhai, 1983; Krashen, 1989). The process by which “incidental” acquisition through reading occurs is slow, however, and there is no way to predict which words will be learned, when, nor to what degree. The question remains as to whether instructional intervention could support the process and make it more directed and efficient. The classroom experiments reported here attempt to do this, using instructional procedures designed to increase the salience and cognitive processing of targeted words encountered by L2 students in reading texts. These experiments track the acquisition of these words using a recently developed instrument, the Vocabulary Knowledge Scale (Paribakht & Wesche, 1993; Wesche & Paribakht, forthcoming).