The Sound of Populism: Distinct Linguistic Features Across Populist Variants

TL;DR

This study analyzes the 'sound' of populism in political rhetoric by combining LIWC-based linguistic features with a fine-tuned RoBERTa classifier to detect four populist flavors (left-wing, right-wing, anti-elitism, and people-centrism) in U.S. inaugural and State of the Union speeches. It leverages 308 US speeches and a German parallel dataset, using LIWC as interpretable predictors and transformer models as dependent-variable scorers, with cross-language validation through translations. Regession analyses reveal distinct patterns: left-wing and anti-elitism favor informality with calibrated discourse, while right-wing and people-centrism exhibit stronger emotional tonality linked to identity and crisis narratives; complexity is often reduced in right-wing rhetoric. These results advance understanding of how linguistic style and emotional resonance contribute to populist messaging, offering a framework that integrates interpretable lexical features with powerful context-aware models for political discourse analysis.

Abstract

This study explores the sound of populism by integrating the classic Linguistic Inquiry and Word Count (LIWC) features, which capture the emotional and stylistic tones of language, with a fine-tuned RoBERTa model, a state-of-the-art context-aware language model trained to detect nuanced expressions of populism. This approach allows us to uncover the auditory dimensions of political rhetoric in U.S. presidential inaugural and State of the Union addresses. We examine how four key populist dimensions (i.e., left-wing, right-wing, anti-elitism, and people-centrism) manifest in the linguistic markers of speech, drawing attention to both commonalities and distinct tonal shifts across these variants. Our findings reveal that populist rhetoric consistently features a direct, assertive ``sound" that forges a connection with ``the people'' and constructs a charismatic leadership persona. However, this sound is not simply informal but strategically calibrated. Notably, right-wing populism and people-centrism exhibit a more emotionally charged discourse, resonating with themes of identity, grievance, and crisis, in contrast to the relatively restrained emotional tones of left-wing and anti-elitist expressions.