Chapter 9 investigates if and how the symptoms of mental illness are present in the MI 1984–2014 Corpus by exploring the symptoms of each disorder type covered by the corpus. Specifically, using keyword and key semantic domain analysis, I explore whether the symptoms of mental illnesses are accurately represented in news articles on mental illness. In addition to corpus tools, I also qualitatively analyse the most prototypical text for each illness subcorpus (i.e. the text that contains the most frequent features of the illness subcorpus overall) to explore whether the keyness findings are also a feature of whole texts.

Chapter 3 provides a brief overview of the particular approach to corpus linguistics adopted in this book: namely, corpus linguistics as a method (as opposed to corpus linguistics as a theory) (McEnery & Hardy, 2012; Tognini-Bonelli, 2001). The specific corpus linguistic analytical methods used, such as collocation and keyness analysis, and the statistical tests and cut-offs associated with each analysis type are detailed. Using data from the MI 1984–2014 Corpus (specifically the data collected during a pilot study and an illness-specific sample of the data), each analytical method used is exemplified. The utility of each analysis type for analysing ideology in texts is also discussed.

This is a ‘quantitative methods’ chapter. It explains the consequences of more advanced developments in quantitative corpus techniques. Two themes are developed. Firstly, some advanced measures improve the range of options available to researchers studying, for example, collocation or keyness. This shows that different measures may give different results. Secondly, some applications of statistical techniques allow the contents of a corpus to be rearranged, leading to novel insights. It is argued that these bottom-up approaches amount to quantitative ‘corpus-driven’ methods. Topics discussed in the chapter are keyness, collostructions, text clustering using lexical bundles and multidimensional analysis, and word clustering using principal component analysis and topic modelling.

Chapter 5 compares the phraseology of usage to exposure. It shows that more than half of patterns extracted from a student’s usage corpus also occur in her exposure corpus. At the same time the figure drops significantly if these patterns are compared to a different student’s exposure corpus supporting the assumption of representativeness. The chapter then proceeds to compare usage patterns to exposure qualitatively focusing on the processes of variation and change. It finds support for the process of approximation through which a more or less fixed pattern loosens and becomes variable on the semantic or grammatical axis presumably due to frequency effects and the properties of human memory. The chapter also proposes a reverse process, fixing, through which the pattern extends and develops verbatim associations through repeated usage. Both processes are suggested to occur within meaning-shifts units and thus be characteristic of co-selection.