title: Neural processing of speech in children is influenced by extent of bilingual experience.
abstract: Language experience fine-tunes how the auditory system processes sound. Bilinguals, relative to monolinguals, have more robust evoked responses to speech that manifest as stronger neural encoding of the fundamental frequency (F0) and greater across-trial consistency. However, it is unknown whether such enhancements increase with increasing second language experience. We predict that F0 amplitude and neural consistency scale with dual-language experience during childhood, such that more years of bilingual experience leads to more robust F0 encoding and greater neural consistency. To test this hypothesis, we recorded auditory brainstem responses to the synthesized syllables 'ba' and 'ga' in two groups of bilingual children who were matched for age at test (8.4 ± 0.67 years) but differed in their age of second language acquisition. One group learned English and Spanish simultaneously from birth (n=13), while the second group learned the two languages sequentially (n=15), spending on average their first four years as monolingual Spanish speakers. We find that simultaneous bilinguals have a larger F0 response to 'ba' and 'ga' and a more consistent response to 'ba' compared to sequential bilinguals and we demonstrate that these neural enhancements track with years of bilingual experience. These findings support the notion that bilingualism enhances subcortical auditory processing.
authors.affiliation: Auditory Neuroscience Laboratory, Evanston, IL, USA(2); Bilingualism and Psycholinguistics Research Group, Evanston, IL, USA; Department of Communication Sciences and Disorders, Evanston, IL, USA; Northwestern University, Evanston, IL, USA.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Krizman
authors.affiliation: Auditory Neuroscience Laboratory, Evanston, IL, USA(2); Department of Communication Sciences and Disorders, Evanston, IL, USA; Northwestern University, Evanston, IL, USA.
authors.forename: Jessica
authors.initials: J
authors.lastname: Slater
authors.affiliation: Auditory Neuroscience Laboratory, Evanston, IL, USA(2); Department of Communication Sciences and Disorders, Evanston, IL, USA; Northwestern University, Evanston, IL, USA.
authors.forename: Erika
authors.initials: E
authors.lastname: Skoe
authors.affiliation: Bilingualism and Psycholinguistics Research Group, Evanston, IL, USA; Department of Communication Sciences and Disorders, Evanston, IL, USA; Northwestern University, Evanston, IL, USA.
authors.forename: Viorica
authors.initials: V
authors.lastname: Marian
authors.affiliation: Auditory Neuroscience Laboratory, Evanston, IL, USA(2); Department of Communication Sciences and Disorders, Evanston, IL, USA; Institute for Neuroscience, Evanston, IL, USA; Department of Neurobiology and Physiology, Evanston, IL, USA; Department of Otolaryngology, Evanston, IL, USA; Northwestern University, Evanston, IL, USA. Electronic address: nkraus@northwestern.edu.
authors.forename: Nina
authors.initials: N
authors.lastname: Kraus
mesh_terms: D000367:Age Factors; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D019303:Multilingualism; D013067:Speech Perception
keywords: Auditory; Bilingual experience; Brainstem; Fundamental frequency; Neural consistency