On two developments of (deontic) must in L1 South African English

Abstract

This paper reconsiders the status of what is normally described as deontic must in L1 South African English (SAE), presently understood as a medium-to-weak obligation marker in the grammar (Wasserman & van Rooy 2014). The paper focuses on two uses of the modal where an additional meaning of the speaker’s desire and wish (for the addressee) parasites on the modal. These two uses also exhibit distinctive morphosyntactic behaviour. The first part of the paper presents recorded data and gives an informal descriptive account of the modal in the two cases of interest. The second part argues that, in these cases, must has undergone a process of change known as pragmaticalization, language change that leads into the discourse domain (Biberauer 2018; Diewald 2011; Müller & Axel-Tober 2025). Tests from Coppock (2012) and Potts (2005) indicate that new discourse-related meaning has lexicalized into the content of the modal in each case, such that it is distinct from the medium-to-weak obligation marker. The paper finally considers the elements of meaning in these two cases that make must different from canonical deontic must, showing how the components of meaning in its canonical interpretation provide optimal material for the SAE interpretation evidenced in this paper. A new label for SAE must is then proposed for the modal.