The Diachrony of Modality and Mood
This chapter surveys recent work on the diachrony of modality, mood, and subjectivity. It first considers the research over the past thirty years into the development of modal forms and meanings—which is largely dominated by the study of English, and more broadly the Germanic languages, in the context of grammaticalization theory. It focuses on the nature of the source constructions for modal forms, on the emergence of epistemic functions from deontic or root modality, and on the role of syntactic development for the emergence of modal meanings. The chapter then discusses work on the diachronic development of mood, focusing on indicative/subjunctive inflection and (ir)realis coding in languages with little written history. It finally looks into diachronic studies and the role of subjectivity and subjectification in meaning changes in the class of modal verbs in languages.