Three experiments were conducted to examine the effects of three types of elaboration—marked paraphrase, unmarked paraphrase, and unnecessary detail—on NNS listening comprehension. Participants (both NSs and NNSs) were asked to listen to instructions and then draw or alter drawings on a page in front of them. The instructions were heard in one of four conditions, the basic set or one of the three elaboration conditions. Subsequent analyses of the participants' comprehension indicated that all listeners had significantly more difficulty following instructions in the unnecessary detail condition than in any other. Marked paraphrase was found to facilitate comprehension in some cases. It was concluded that the quality of elaboration has implications for listening comprehension, in both the classroom and the workplace.

This study focuses on the impact of different variables on the nature of language performance in the context of task-based instruction. Characteristics of tasks are discussed, and then a framework is offered that can organize the nature of task-based instruction and relevant research. The framework is used to generate predictions regarding the effects of three different tasks (Personal Information Exchange, Narrative, and Decision-Making) and three different implementation conditions for each task (unplanned, planned but without detail, detailed planning) on the variables of fluency, complexity, and accuracy. The study reports strong effects of planning on fluency and clear effects also on complexity, with a linear relationship between degree of planning and degree of complexity. However, a more complex relationship was discovered between planning and accuracy, with the most accurate performance produced by the less detailed planners. In addition, interactions were found between task type and planning conditions, such that the effects of planning were greater with the Narrative and Decision-Making tasks than with the Personal Information Exchange task. The results are discussed in terms of an attentional model of learning and performance and highlight the importance of tradeoff effects between the goals of complexity and accuracy in the context of the use of limited capacity attentional resources. The study contributes to the development of cognitive models of second language performance and addresses a number of pedagogic issues.

This paper argues that the study of second language acquisition theory and pedagogy can be enhanced through the use of time-series research designs. As quasi-experiments, time-series designs have features that improve internal validity. In addition, because these designs only require a small number of subjects, they are very practical, encouraging a greater number of empirical investigations of the many claims within the field and permitting the use of authentic measures that have high construct validity. The longitudinal nature of the designs also enhances construct validity, potentially yielding new insights into the effects of instruction on SLA. The designs utilized in two time-series studies (Kennedy, E., 1988, The Oral Interaction of Native Speakers and Non-Native Speakers in a Multicultural Preschool: A Comparison between Freeplay and Contrived NS/NSS Dyads, unpublished master's thesis, University of British Columbia, Vancouver; Mellow, J. D., 1996, April, A Longitudinal Study of the Effects of Instruction on the Development of Article Use by Adult Japanese ESL Learners, unpublished manuscript, University of British Columbia, Vancouver) are reviewed in order to illustrate the design features, the questions that may be investigated, and the issues that are raised in interpreting data.