Perceptual Rhythmic Ability Predicts Cognitive Load in Perception of Accented Second Language Speech

Purpose: The present study examined whether perceptual rhythmic ability predicts cognitive load during second language (L2) speech perception, and whether this effect depends on rhythmic interference from listeners’ first language (L1) or on rhythmic alignment with the L2 target language.Method: Eighty-two L1 Spanish–L2 English bilinguals completed a pupillometry experiment in which they listened to English sentences spoken with accents differing in rhythmic properties (American-accented English: higher variability or more stress-timed; Spanish- and Mandarin-accented English: lower variability or more syllable-timed). Cognitive load was indexed using pupil dilation during listening. Participants also completed a perceptual rhythm discrimination task, along with additional control tasks relevant to L2 speech processing.Results: Overall, listeners with stronger perceptual rhythmic ability exhibited greater pupil dilation during L2 English listening compared to listeners with weaker rhythmic ability. However, this difference was reduced for American-accented English relative to Spanish-accented English, suggesting that rhythmic alignment between the accent and the target language facilitates processing.Conclusions: The findings indicate that perceptual rhythmic ability is associated with greater cognitive load during L2 English speech perception across accents in L1 Spanish speakers, likely reflecting differences in rhythmic properties between languages. Moreover, alignment between listeners’ rhythmic sensitivity and the rhythmic properties of the target language plays a critical role in shaping cognitive load during L2 speech processing. Future research should examine how rhythmic sensitivity interacts with other factors across diverse L2 listening contexts and populations.