Intelligible nonnative-accented speech incurs a processing cost: Converging evidence from a behavioral and a physiological paradigm

Abstract

In noisy settings or when listening to an unfamiliar talker or accent, it may be difficult to understand spoken language. This difficulty can result in reductions in speech intelligibility, but may also increase the effort necessary to process the speech. In the current study we used a dual-task paradigm and pupillometry to assess the cognitive costs associated with processing fully intelligible accented speech, predicting that participants would expend greater effort when processing nonnative-accented speech, and that this cost would be attenuated over time. Consistent with our hypothesis, the behavioral and physiological paradigms provided converging evidence that listeners expend greater effort when processing nonnative- relative to native-accented speech. We also observed an overall reduction in listening effort over the course of the experiment and found some evidence for greater perceptual adaptation to nonnative-accented speech. These results suggest that even when speech is fully intelligible, resolving deviations between the acoustic input and stored lexical representations incurs a processing cost, and adaptation may attenuate this cost.