This chapter will focus on the period of particularly rapid change in early Modern English in which the status of modals and auxiliaries was substantially clarified. Lightfoot (1979) interpreted this as showing the development of a class ‘modal’. My views differ from his in many respects. But we agree that the beginning of early Modern English saw a particularly significant set of changes, as (with less enthusiasm) does Plank (1984, see 348). In discussing this, I will need to recap some work familiar particularly from these authors, but my interpretation will differ and I will cover a wider range of data than Lightfoot.

We can conceptualize early Modern English changes affecting auxiliary group verbs under three headings. First comes a series of changes to earlier properties which further differentiate the modal group from full verbs: these are (A)–(D) of §9.1 below. Second is a striking further series of changes which look like new developments. These tend to make the auxiliary group more coherent and distinct. I will argue that both these sets of changes are illuminatingly interpreted as the development of a ‘basic-level’ category within Rosch's approach to categorization. Finally there is the general adoption of periphrastic DO. This must surely be interinvolved with these other changes if only because of the striking coincidence of date, but the nature of the connection is less clear. I will consider what other factors might be involved, and will sketch a speculative account relating changes in the status of finiteness to changes in word order, the obligatoriness of subjects, and the rise of periphrastic do.