Modal coherence in specialised discourse: a case study of persuasive oral presentations in business and academia

The multimodal character of academic and business discourse has long been acknowledged. Several studies have brought to the fore the multimodal nature of academic and business genres, and have shown that spoken or written words are only one among the many resources available to convey meaning (Carter-Thomas & Rowley-Jolivet, 2003; Kast, 2008; Querol-Julian & Fortanet-Gomez, 2012, 2014; Morell, 2014, 2015). In particular, in the case of persuasive oral genres within business and academia, semiotic modes such as gestures (Kendon, 2004) or intonation (Brazil, 1997) play a crucial role in the design of a persuasive message. This is the case of conference presentations, research dissemination talks and product pitches. In these genres speakers have been shown to resort to multimodal persuasive strategies to craft an effective presentation (Valeiras-Jurado & Ruiz-Madrid, 2015; Valeiras-Jurado, 2015; Valeiras-Jurado, Ruiz-Madrid & Jacobs, 2018). This paper probes into what exactly makes these persuasive presentations effective. Specifically, the question addressed is whether it is the choice of persuasive strategies, the number of semiotic modes, or the consistency in the use of these modes (i.e. modal coherence) that affects persuasion more directly. The case study presented in this paper compares a research dissemination talk and a product pitch. The study combines video-based, computer-aided multimodal discourse analysis (MDA) with ethnographic interviews. The results suggest that modal coherence is of crucial importance for the effectiveness of a persuasive presentation. Likewise, several practices detrimental to persuasion are identified. These findings have interesting pedagogical implications, since they can contribute with a genre-based, multimodal methodology to the teaching of English for Specific Purposes (ESP).