Introduction

In the previous chapters I reviewed several theories of grammar and we saw how language teachers and SLA researchers drew on these theories to define ‘grammar’ in their work. I also discussed how different instructional practices influenced how learners acquire knowledge of a second or foreign language grammar. Implicit in this discussion was the notion that knowledge of the L2 grammatical system can be demonstrated by a learner on some outcome measure, whatever form that might take, and that teaching can potentially influence the results obtained on this measure. From the results of these assessments, we can then make inferences about the students' grammatical ability, which would subsequently provide an empirical basis for decision-making. For example, language teachers use test results to make decisions about student placement in a language program or about the degree to which their students have mastered the material in a course, and SLA researchers use test results to make decisions about whether young learners acquire grammatical features better than older learners. Implicit was also the notion that if more than one assessment of grammatical ability was obtained over time, inferences related to grammatical learning or even the effectiveness of instruction could be determined based on the observed changes in what learners demonstrate on these measures. This information is of particular concern to language teachers, testers and SLA researchers for making instructional recommendations and for theory-building.