Current change in the modal system of English
This paper takes the variation between <i>must, have to</i> and <i>have got to</i> as a window through which to view changes in the modal system in Present-Day British English (1960s–1990s). The results from this study show a dramatic decrease in frequency of the core modal <i>must</i> and a significant increase in frequency of the semi-modal <i>have to</i> in the <i>Diachronic Corpus of Present-Day Spoken English</i> (DCPSE). Changes in the modal system affect both epistemic and root uses of <i>must</i>, although <i>have to</i> is only an active rival to root <i>must;</i> epistemic instances of <i>have to</i> (and <i>have got to</i>) are rare in the corpus. We suggest that a tendency to avoid expressions of strong commitment is the cause of the decline in <i>must</i>. This is supported by similar falls in the frequency of <i>should</i> and <i>ought</i> found by Leech et al. (2009).