The project traced the historical development of the ‘conditional’ use of modal verbs in the West Germanic (WG) languages, seen in 'If there should be a problem/Should there be a problem, don’t hesitate to call.'
While the rise of ‘postmodal’ uses of modal verbs is usually viewed as semantic change, the current project tested the hypothesis that the development of their ‘conditional’ use can be analysed as a syntactic change, as different structural positions can be shown to correlate with the different modal meanings on the assumed grammaticalisation cline. The research hypothesis was that the modal verb in question undergo an ‘upward’ reanalysis through the clausal hierarchy under Roberts/Roussou’s (2003) generative approach to grammaticalisation, which by linking grammaticalisation clines to hierarchical functional clause structure makes precise predictions about what are possible changes. Empirical evidence are the kinds of co-occurrence and ordering restrictions that the modal verb display w.r.t. other, in particular lower, modal expressions at different diachronic stages.