Neural representation of linguistic feature hierarchy reflects second-language proficiency
Giovanni M. Di Liberto,
Jingping Nie,
Jeremy Yeaton,
Bahar Khalighinejad,
Shihab A. Shamma,
Nima Mesgarani
Affiliations
Giovanni M. Di Liberto
Laboratoire des systèmes perceptifs, Département d’études cognitives, École normale supérieure, PSL University, CNRS, 75005 Paris, France; Corresponding authors.
Jingping Nie
Department of Electrical Engineering, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, United States
Jeremy Yeaton
Laboratoire des systèmes perceptifs, Département d’études cognitives, École normale supérieure, PSL University, CNRS, 75005 Paris, France; Laboratoire de Psychologie Cognitive, UMR 7290, CNRS, France. Aix-Marseille Université, France
Bahar Khalighinejad
Department of Electrical Engineering, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, United States
Shihab A. Shamma
Laboratoire des systèmes perceptifs, Département d’études cognitives, École normale supérieure, PSL University, CNRS, 75005 Paris, France; Institute for Systems Research, Electrical and Computer Engineering, University of Maryland, College Park, USA
Nima Mesgarani
Department of Electrical Engineering, Columbia University, New York, NY, USA; Mortimer B. Zuckerman Mind Brain Behavior Institute, Columbia University, New York, NY 10027, United States; Corresponding authors.
Acquiring a new language requires individuals to simultaneously and gradually learn linguistic attributes on multiple levels. Here, we investigated how this learning process changes the neural encoding of natural speech by assessing the encoding of the linguistic feature hierarchy in second-language listeners. Electroencephalography (EEG) signals were recorded from native Mandarin speakers with varied English proficiency and from native English speakers while they listened to audio-stories in English. We measured the temporal response functions (TRFs) for acoustic, phonemic, phonotactic, and semantic features in individual participants and found a main effect of proficiency on linguistic encoding. This effect of second-language proficiency was particularly prominent on the neural encoding of phonemes, showing stronger encoding of “new” phonemic contrasts (i.e., English contrasts that do not exist in Mandarin) with increasing proficiency. Overall, we found that the nonnative listeners with higher proficiency levels had a linguistic feature representation more similar to that of native listeners, which enabled the accurate decoding of language proficiency. This result advances our understanding of the cortical processing of linguistic information in second-language learners and provides an objective measure of language proficiency.
