Evidential verbs in the genre of medical posters. A corpus-based analysis

The main goal of this volume is to analyze evidentiality expressed with verbs and realized in a corpus of specialized written texts, namely medical posters, with the purpose of exploring the categories, forms and functions of evidentiality in medical discourse. Drawing on relevant literature on evidentiality, the volume is based on the assumption that evidentiality does not entail evaluation. It also claims that, in medical discourse, all evidentiality is intersubjective, in the sense that a poster author shares his/her evidence with a disciplinary audience and the relation between responsibility attribution and the information conveyed through the factual claims asserted determines the type of evidential category. Indeed, in medical discourse, these relations can have different functions from those established by evidential literature in common discourse. By combining two corpus linguistics tools (i.e. WordSmith Tools and WMatrix) in a methodological approach to the study of evidentiality, a corpus-based investigation about the written component of 447 medical posters is carried out to analyze expressions of verbal evidentiality (that is, evidential verbs) asserting factual claims expressed through specific combinations of linguistic and discursive features. More specifically, the methodological approach required (1) an appropriate definition of evidential classification; (2) the elaboration of a framework to be applied to a sample corpus in order to (3) systematically identify evidential lexical markers, on the basis of which (4) evidentiality is detected in the main corpus thanks to a corpus-based approach (Wordsmith Tools and WMatrix). The data analysis, carried out both quantitatively and qualitatively, demonstrates that textual expressions can realize different verbal evidential functions according to the context. In some cases, one textual evidential marker can indicate different categories of evidentiality. In other cases, one textual evidential marker may simultaneously have overlapping categories, which depends on the relationship between the entity indicating the source of knowledge and the factual claim. The implications can be of relevance to students and scholars of English for Academic and Specialized Purposes in order to see whether these evidential characteristics are similar to or different from general language, and if so, to what extent and for what reasons. The aim is to make a practical contribution to language in use in a field which has seldom been investigated, and to show how researchers use the discipline’s linguistic resources to convey scientific knowledge.