Gestural Cosuppositions within the Transparency Theory

1 New Debates on Co-speech Gesture Semantics

Following initial formal work on the semantic integration of gestures in discourse (e.g., Lascarides and Stone 2009) and on iconic aspects of gestural semantics (Giorgolo 2010), there has recently been a resurgence of interest in the formal and experimental semantics of co-speech gestures. It was motivated on three fronts: co-speech gestures have become crucial to understanding whether spoken language has means of iconic enrichment similar to those of sign language (Goldin-Meadow and Brentari 2017); co-speech gestures have become the topic of new debates in theoretical semantics, pertaining to their proper place in the inferential typology (Ebert and Ebert 2014, Schlenker 2018a); and experiments have been conducted to try to adjudicate these new debates (e.g., Tieu et al. 2017, 2018).

First, co-speech gestures became crucial to conducting a proper comparison between the semantics of signed and spoken languages. Iconic modulations (i.e., modifications of a lexical sign to represent aspects of the denoted object or events) are a notoriously fertile means of semantic enrichment in sign language, but they are more impoverished in spoken language. For instance, in ASL (American Sign Language) the movement of the hands realizing the verb GROW can be made faster or broader to denote a growth process that is quicker or of greater amplitude (Schlenker, Lamberton, and Santoro 2013). In English, the vowel of the adjective long can be modulated to refer to a very long process (Okrent 2002), as in The talk was looong (see also Fuchs et al. 2018). But it is clear that intrinsic limits of vocal iconicity make this a relatively circumscribed process. By contrast, co-speech gestures afford a fertile means of iconic enrichment of speech, one that is prima facie comparable to iconicity in sign. This motivated Goldin-Meadow and Brentari's (2017) intimation that sign with iconicity should be compared to speech with co-speech gestures rather than to speech alone.

The question, however, is whether iconic modulations in sign are genuinely similar to iconic enrichments of speech by way of co-speech gestures. With respect to the iconic information that is conveyed, the similarity might be real. But on another front, results from the recent literature on signs and gestures highlight an important difference: in Schlenker 2018b, I argue that iconic modulations (i.e., the modification of a sign or word rather than its enrichment by an external addition) can often make an at-issue contribution. Thus, the sentence If the talk is loooong, I'll leave before the end can be understood to make the same kind of (at-issue) claim as If the talk is very long, I'll leave before the end. Similar observations were made about iconic modulations of GROW in ASL. By contrast, researchers have suggested in different ways that co-speech gestures do not make at-issue contributions, at least not in the absence of a (potentially costly) process of adjustment.

Two types of non-at-issue content have played a prominent role in recent debates on co-speech gestures. Presuppositions are characterized by their projective behavior: they are inherited by complex sentences in ways that distinguish them from at-issue entailments as well as from other pragmatic inferences. Thus, x regrets q-ing presupposes that x q-ed; the presupposition is inherited by yes-no questions as in (1a) and gives rise to a universal inference under none-type quantifiers as in (1b) (see Chemla 2009 for experimental results).

(1)

a. Does Ann regret helping her daughter?
⇒ Ann helped her daughter

b. None of these 10 women regrets helping her daughter.
⇒ each of these 10 women helped her daughter

Supplements are the semantic contributions of appositive relative clauses; they are thought not to interact scopally with operators, and thus to always have "wide scope" behavior (Potts 2005), as illustrated in (2) (I will refine this point shortly).

(2)

a. Did Ann help Robin, who was taking an exam?
⇒ Robin was taking an exam

b. None of these 10 women helped Robin, who was taking an exam.
⇒ Robin was taking an exam

In pioneering work, Ebert...