Should vocabulary instruction be integrated or isolated?

This study compares integrated and isolated form-focused instruction for vocabulary development in an English as a second language (ESL) reading lesson. Two classes of ESL learners (N = 20) from a university preparation academic English course were involved in the study. Each class did two reading treatments in which they read an article and studied vocabulary from that article. In one of the treatments participants were taught the words in isolation prior to reading the article, and in the other the vocabulary instruction was integrated with reading the article. Paribakht and Wesche's (1997) vocabulary knowledge scale was used as the instrument to measure learning and retention gains for words taught in isolated instruction, in integrated instruction, and words acquired incidentally. Statistical analysis showed both types of instruction led to more learning and retention of vocabulary knowledge than incidental exposure alone. Although retention rates were similar for isolated and integrated instruction, there was a trend for isolated instruction to lead to higher rates of learning