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Cortical Tracking of Code-Switching in Naturalistic Speech Perception: Insights from Spanish-English Bilinguals
Poster Session E, Sunday, September 14, 11:00 am - 12:30 pm, Field House
This poster is part of the Sandbox Series.
Ana Happle1, Prarthana Shivabasappa1, Edward C Brown2; 1New Mexico State University, 2University of Tennessee
Code switching is a critical tool for successful communication between bilingual speakers with overlapping linguistic backgrounds, aiding speakers in contextual adaptation and enhancing listener understanding (Beatty-Martinez et al., 2020; Rayo et al., 2024). In this ongoing study, we have investigated the impact of code-switching on neural correlates of speech perception for a cohort of simultaneous Spanish-English bilinguals from the US-Mexico border region. Specifically, we evaluated how code-switching impacts cortical tracking of speech, an electrophysiological readout of acoustic and linguistic encoding during comprehension (Meyer et al., 2020; Obleser & Kayser, 2019). We recorded 64-channel EEG while healthy adult participants (current n = 23) listened to three naturalistic passages (~3 minutes each) that were constructed so as to contain approximately 50% Spanish content & 50% English. Intra-sentential switching and inter-sentential switching were embedded in each passage with equal frequencies of occurrence. Using a forward modeling approach (Crosse et al., 2016), we quantified cortical tracking of the broadband (1-25Hz) and narrowband envelopes in the delta (1-3Hz), theta (3-5Hz) frequency ranges, which correspond to the rate of phrases and words in the continuous speech stream (Lakatos et al., 2008). Preliminary findings indicate significant word tracking in the theta band, which predicted characteristics of participants’ language usage history. Specifically, increased bilingual speaking experiences improved speech tracking, while increased hearing exposure to participants’ second language decreased speech tracking. These findings suggest that speaking experiences may provide a more flexible neural architecture that may be better suited for unpredictable linguistic dynamics of bilingual communication. However, listening exposure may lead to a more rigid auditory model that may be monolingual-centric, resulting in less efficient speech encoding when codeswitching occurs. Planned additional analyses will evaluate the impact of code-switching type and the direction of the switch (Spanish to English vs. English to Spanish) on cortical tracking, as well as how such factors impact encoding latencies as evidenced by multivariate temporal response functions. These findings inform understandings of neural function for bilinguals when listening to naturalistic speech that contains code-switching. Future work may build upon these findings by evaluating the relationship between code-switching and cortical tracking of self-produced speech.
Topic Areas: Multilingualism, Speech Perception