This paper discusses the composition and application in teaching of the Contemporary written Italian corpus (CWIC), created at Griffith University as a resource for Italian students at intermediate level. Since 1998, CWIC has been used in our second-year and third-year courses, primarily as a reference tool while writing. Our rationale in introducing CWIC drew particularly on the idea that learners armed with a corpus can act as researchers who discover rules about language for themselves, by formulating and testing hypotheses with reference to authentic examples of word use in context, as outlined by Johns (1991b). We conducted a gradual and guided apprenticeship in corpus use over a whole semester, intended to prepare the students sufficiently to work independently with CWIC when a web-based version comes online. We then sought to evaluate the effectiveness of the students? investigations and identify the difficulties they encountered when working without a teacher. Although the students were very enthusiastic about using CWIC, our analysis of their investigations showed they were less successful than we had anticipated. In particular, it highlighted two types of problems ? in managing a hypothesis-testing process and in observation of data ? that significantly reduced their effectiveness in the ?learner as researcher? role. We are seeking to address these difficulties by changing the objectives and priorities of our training. A key element in our response is to introduce students to CWIC with an ?observe and borrow? mentality first, before progressing to an ?observe and derive rules? approach such as we had originally envisaged would be the norm.