Exploring the complexity of 'can', 'could' and 'be able to' through corpus analysis and classroom- and coursebook-based investigation
The purpose of this study is to investigate the central modal auxiliaries CAN and COULD, and the quasi-modal BE ABLE TO, together with their negative forms, and from this investigation, make a contribution to English language learning pedagogy. This study uses analysis of the spoken and written components of the British National Corpus (≈ 100 million words) to gain a better understanding how these modal auxiliaries are used by native and native-like speakers of English. It also draws on a classroom data set (68,265 words), containing a spoken and written component, to investigate how they are being used by students and an instructor. Furthermore, these modal auxiliaries are examined in an English language learner coursebook, New Headway series (441,760 words). This study uses both quantitative and qualitative methods for analysis. In the first phase of this investigation, previous literature along with an examination of each modal auxiliary form in a sample BNC data set were used iteratively to establish meaning categories for CAN, COULD and BE ABLE TO. In the second phase, overall frequencies were obtained from each data source. And finally, based on the categories of meanings found, in the third phase, meaning frequencies for all three data sources were determined. Taking these overall frequencies and meaning frequencies into consideration, comparisons were made between the classroom and the BNC, and New Headway and the BNC. As a result of the investigations above, this study found ‘possibility’ to be the predominant meaning for CAN, COULD and BE ABLE TO with a subset of meaning categories. The subset of categories identified is larger than previously identified in literature. Context played a central role in interpreting these meanings of modal auxiliaries and this study suggests that it would be beneficial for anyone writing about modal auxiliaries to fully account for context when modal meanings are being examined, especially in pedagogical materials. As a result, included in this study are instances with expanded criteria. Focusing on the classroom, this study shows not all meaning categories are present in the classroom data set and also suggests that students may benefit from explicit instruction around the role and communicative effects of these modal auxiliaries in various social contexts. Moving to the New Headway series, this study demonstrates that the meaning frequencies for some categories (e.g. ability) were higher in frequency than the British National Corpus due to the inclusion of contrived example conversations. Taking these and other findings in the study into consideration, this thesis raises awareness of the complexities of understanding and conveying these modal auxiliaries and concludes with recommendations for instructors in English language classrooms.