Comparative modals: (Dis)similar diachronic tendencies

This article examines modal expressions with the comparative adverbs better, rather and sooner in American English, and assesses to what extent they have grammaticalized. The corpus data offer evidence that the three comparative modal groups exhibit considerable phonetic reduction in the 1810–2009 period studied. Analysis of several aspects of the constructions, such as subject types, temporal reference and comparative meaning, reveals which conditions promoted this erosion. However, the data also indicate that the three groups are semantically and constructionally quite heterogeneous. In fact, this article proposes a grammaticalization scenario for the rather and sooner structures that is different from the one posited for the better structures.