Linking speech acoustics to listener perception and experience in dysarthria

Abstract

Dysarthria, a motor speech disorder, is often treated as a problem of intelligibility. However, individuals with dysarthria have reported reduced communicative effectiveness even when their speech remains intelligible (Dykstra et al., 2015). Recent research has shown that listeners experience greater cognitive effort when processing dysarthric speech (Fletcher et al., 2022; Hirsch et al., 2025), highlighting that intelligibility alone may not capture the listener’s experience. This study challenges the assumption that intelligibility alone ensures communicative success by investigating the acoustic correlates to emotional perception and listener affect in dysarthric speech. Speech samples from 32 speakers with varying types of dysarthria were acoustically analyzed and presented to 50 naïve listeners. After hearing each sample, listeners rated speech intelligibility, pleasantness, and animation and their own comfort, frustration, and fatigue while listening. Correlation analysis showed medium to large associations between scales, supporting the conclusion that listeners form global impressions that integrate both intelligibility and emotion. Among the acoustic measures examined, articulation rate, speech rate, and F2 slope emerged as the most consistent and robust predictors of ratings across scales. Overall, the convergence of listener ratings and their shared acoustic predictors suggests that intelligibility, emotion, and listener affect are not perceptually independent in dysarthric speech.