抄録
Collaborative speaking tasks affect vocabulary learning. In particular, the negotiation of words (i.e., negotiating form or meaning of words) during a task facilitates the acquisition of productive vocabulary knowledge. Many studies have examined task taxonomies and the effects of task characteristics. Few studies, however, have examined differences in the effects of task characteristics on vocabulary learning. The present study, therefore, investigated the effects of decision-making tasks—a type of communication task—on learning productive vocabulary. Japanese EFL students (52 high school and 19 university students) were given a text related to the task topic and instructed to discuss the topic in English for 15 minutes. A modified vocabulary knowledge scale was used before and after the task to measure the vocabulary knowledge acquired. Task output was also analyzed to examine the relationship between word engagement and the learning of target words. The results suggest that decision-making tasks can support the learning of unfamiliar words.
