Public defence of William Noble's doctoral thesis

Presented by: William Noble
Date: April 20, 2023

Cordially welcome to the public defence of William Noble's doctoral thesis on Thursday 20 April, at 13:15 in room J222, Renströmsgatan 6, Faculty of Humanities. The title is "Semantic change in interaction: Studies on the dynamics of lexical meaning".

Doctoral candidate: William Noble, University of Gothenburg

Supervisor: Staffan Larsson, University of Gothenburg Assistant supervisor: Asad Sayeed, University of Gothenburg

Opponent: Associate professor Casey Kennington, Boise State University

Committee: Professor Hana Filip, Heinrich Heine Universität, Düsseldorf Associate Professor, Jakub Szymanik, University of Trento Docent Dana Dannells, Göteborgs universitet

Chair: Professor Eleni Gregoromichelaki, Göteborgs universitet

Date: 2023-04-20

Title: Semantic change in interaction: Studies on the dynamics of lexical meaning

Abstract: This compilation thesis investigates how word meanings change. In particular, it's concerned semantic change at the levels of interaction and the speech community. To this end, the compiled studies employ methods from both formal and computational semantics.

The first study presents a model for, and companion annotation study of, word meaning negotiation, a conversational routine in which the meaning of a word becomes an explicit topic of conversation. The next two studies introduce and apply classification systems, a model of communal conceptual resources for ordering and talking about a particular domain. We use a formalization thereof to model how genus-differentia definitions can be used in interaction to update lexical knowledge of perceptual categories. The next study considers a related phenomenon, perceptual category description, but this time from a computational perspective. By modeling a short interaction between two neural networks, we investigate how different ways of representing perceptual categories affect linguistic grounding. Following that, we turn to the dynamics of social meaning, particularly the meaning of implicit conversational assumptions called topoi, with a focus on situations of involving uncertainty about the speaker's social identity. The final two studies of the thesis shift the focus from particular interactions to the level of the community. First, we investigate linguistic variation using community conditioned language models to learn vector representations for a collection of online communities. These language-based representations are found to correlate with community representations based on community membership alone. Finally, we use diachronic distributional word vectors to study short-term semantic shift in online communities. We find that semantic change has a significant yet nuanced relationship with the social structure of the community. Altogether, the compilation offers two main insights. First, semantic plasticity is directly related to the complexity of the lexical semantic system. Words exhibit both perceptual and inferential meaning potential, each of which play a role in conveying and learning new words. Monolithic representations of word meaning belie a structured flexibility that guides how words can be used, while providing opportunities for innovation. It is this flexibility that is often the site of new conventionalized meanings. Second, semantic change is rooted in the interactive practices of the community. Communities sustain the communicative norms that govern how linguistic interaction takes place. These norms provide a framework for negotiating meaning. They also comprise the social and semiotic context that supports semantic innovation and change.

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