Listening Effort Across Non-Native and Regional Accents: A Pupillometry Study

Area of Science:

• Psycholinguistics
• Cognitive Science
• Speech Processing

Background:

• Second language (L2) accented speech processing incurs cognitive load.
• The processing cost of non-native first language (L1) accents remains understudied.

Purpose of the Study:

• To investigate the cognitive processing costs associated with different L1 and L2 English accents.
• To compare pupil dilation responses to familiar L1, less-familiar L1, and L2 accented speech.

Main Methods:

• Comparative pupil dilation was used to measure cognitive load in listeners.
• Participants processed sentences in four accents: Southern British English, American English, Glaswegian English, and Mandarin Chinese-accented English.

Main Results:

• Mandarin Chinese-accented English elicited significantly larger pupil dilation than Southern British English.
• Less-familiar L1 accents showed distinct pupil dilation patterns, indicating varied processing.
• American English, despite high intelligibility, incurred a greater cognitive cost than Glaswegian English, contrary to subjective reports.

Conclusions:

• Accurately perceived and intelligible L1 accents like American English incur a cognitive processing cost.
• L2-accented speech incurs a greater cognitive cost than even less-familiar L1 accents.
• Pupil dilation reveals processing costs not always captured by subjective effort measures or intelligibility.