Schlenker, Philippe: 2015. Gesture Projection and Cosuppositions.  Manuscript, Institut Jean-Nicod and New York University.

[Full paper at LingBuzz]

Abstract:    In dynamic theories of presupposition, a trigger pp' (e.g. it stopped raining) with presupposition p (it rained) and assertive component p' (it doesn't now rain) comes with a requirement that p should be entailed by the local context of pp'. We argue that some co-speech gestures should be analyzed within a presuppositional framework, but with a twist: an expression p co-occurring with a co-speech gesture G with content g comes with the requirement that the local context of p should guarantee that p entails g; we call such assertion-dependent presuppositions 'cosuppositions'. We show that this analysis can be combined with a predictive analysis of local contexts (e.g. Schlenker 2009) to account for complex patterns of gesture projection in quantified and in attitudinal contexts, and compare our account to two potential alternatives: one based on supervaluations, and one that treats co-speech gestures as supplements (Ebert and Ebert 2014). We argue that the latter is correct, but for 'post-speech' gestures (= gestures that come after the expressions they modify), rather than for co-speech gestures.