The metapragmatics of authentication in electronic word-of-mouth: exploring the nexus of authenticity and identity in multimodal YouTube reviews from an audience perspective

This dissertation examines the metapragmatic authentication practices of users in the context of electronic word-of-mouth (eWOM) on YouTube. Within a highly interactive discursive environment, reviewers produce multimodal product reviews driven by a range of motivations: From altruistic intentions to support informed purchasing decisions to economically motivated interests. At the same time, recipients engage with eWOM not only for information acquisition but also for social orientation. Against a backdrop of relative anonymity and widespread scepticism regarding potential financial incentives of reviewers, comment sections play a central role, as they serve as spaces where authenticity and identity are actively negotiated and evaluated. Despite the evident importance of authenticity within this genre, there has so far been no systematic investigation of the relationship between authentication and identity construction in multimodal eWOM formats. This dissertation addresses this research gap by developing an integrative analytical model that operationalizes authenticity and identity from an audience-centered perspective. Methodologically, the study adopts an interdisciplinary approach, combining corpus-based discourse analysis, corpus linguistics, critical discourse analysis, and corpus-pragmatic methods. The empirical basis consists of a large corpus of 719,630 YouTube comments, focusing on two key subgenres: technology and beauty reviews. The analysis is conducted on three interrelated levels. First, from a semantic-conceptual perspective, it examines which features of authenticity are explicitly named by users or implicitly constructed through related evaluative categories such as credibility, honesty, and trustworthiness. Second, it focuses on conceptual-relational dynamics, particularly discursive practices of identity attribution through labelling, by which reviewers are either legitimized or delegitimized. Third, a genre-functional perspective takes into account the specific socio-technical conditions of YouTube to analyse how platform logics, user expectations, and participation motives both enable and constrain authentication practices. The findings show that authentication is predominantly implicit and closely tied to processes of identity attribution. Authenticity emerges as a central structuring principle within the genre. Furthermore, the study suggests that the multimodal affordances of YouTube contribute to a functional shift in eWOM: while text-based formats are primarily information-oriented, video-based environments shift the focus toward relational interaction and entertainment value. In addition, subgenre-specific differences can be observed, manifesting in varying dimensions of authenticity, different forms of identity construction, and divergent participation motives. The dissertation begins by outlining the theoretical and contextual foundations of eWOM and YouTube, then elaborates on the concepts of authenticity and identity, and finally presents the methodological design and empirical analyses. A concluding critical discussion integrates the theoretical and empirical findings, reflects on methodological limitations, and outlines directions for future research. Overall, the dissertation contributes to the audience-centered study of digital discourse, particularly in analysing the linguistic construction of authenticity and identity. Its findings are relevant not only to sociolinguistics and discourse analysis but also offer insights for related fields such as marketing, media and communication studies, as well as genre and platform research.