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

Languages differ in their rhythmic properties; for instance, English has higher temporal variability (is more stress-timed) than Spanish. Although previous research has shown that perceptual rhythmic ability can influence the intelligibility of accented speech in L1 English listeners, it remains unclear whether this benefit extends to L2 listening and to cognitive load. Therefore, we examined how perceptual rhythmic ability predicts cognitive load during listening in L1 Spanish–L2 English bilinguals, while controlling for other factors that may influence it. Cognitive load was indexed via pupil size as participants listened to English sentences spoken with Spanish, American, and Mandarin accents. Overall, individuals with stronger perceptual rhythmic ability exhibited greater cognitive load when processing L2 English, for which rhythm diverges from Spanish, compared to those with weaker perceptual rhythmic ability. Notably, this difference was reduced in the American-accented English condition, suggesting that the rhythmic alignment between accent and target language facilitates processing.