Search Abstracts | Symposia | Slide Sessions | Poster Sessions
Cortical speech tracking during bilingual conversations.
Poster Session A, Wednesday, September 30, 11:00 am - 1:00 pm, Wangari Maathai
This poster is part of the Sandbox Series.
James Baybas1, Dorothy Yuxi Lin1, Sharon Lu1, Jonathan Brennan1; 1University of Michigan
Introduction. Bilingual interlocutors seamlessly alternate between languages within or across utterances, known as code-switching (Poplack, 1980). Bilinguals find it easier to code-switch than be constrained to a single language (Zhu et al., 2022). Models of bilingual cognition posit increased difficulty in both production and processing of code-switches due to languages competing for activation (Declerck & Philipp, 2015). Neurocognitive evidence has shown increased processing load for code-switches relative to single-language conditions (van Hell, 2019). Such processing costs are typically observed in studies where language is decontextualized and social interaction is absent; the mere presence of a bilingual during a reading task has been shown to reduce costs (Kaan et al., 2020). Furthermore, Blanco-Elorietta & Pylkkänen (2017) found significant code-switch-specific activation in auditory cortices while participants passively listened to a bilingual conversation, potentially indicating special sensitivity to the acoustic cues present in code-switches. Research on prosodic cues supports this perspective: Zeng (2024) found code-switch production coincides with pitch reset and broader pitch ranges. Additionally, Salig et al. (2026) demonstrated that participants make better predictions of code-switches when additional auditory context of the speaker is provided during a listening task. Acoustic cues, combined with adaptation to an interlocutor’s speech patterns, may provide sufficient information to circumvent processing difficulties brought on by intra-sentential code-switches. We conducted an electroencephalography (EEG) experiment where bilingual participants engaged in a natural bilingual conversation to evaluate how cortical tracking to speech acoustics reflects sensitivity to code-switching. Method. We recorded EEG from 30 adult Mandarin-English bilinguals (Mage = 21.6) during an hour-long bilingual conversation with another Mandarin-English bilingual. Most participants were L1 Mandarin, L2 English speakers as evaluated by proficiency measures (LEXTALE; Lemhöfer & Broersma, 2012; Chan & Chang, 2018) and questionnaires (Marian et al., 2007). Conversations were Mandarin-dominant with spontaneous English code-switches. To focus on the role of acoustic cues in processing code-switches, we propose an analysis using multivariate temporal response functions (Crosse et al., 2016). We model EEG response to speech based on acoustic and linguistic predictors (e.g., acoustic envelope, spectrograms, word onsets, code-switch onsets). We investigate how participants’ cortical tracking of speech differs between early versus later instances in conversation with a novel interlocutor (adaptation), and between periods with higher versus lower density of code-switches. Predictions. For adaptation, if attention wanes with increasing conversation length, we may expect a reduction in cortical tracking; however, if experience increases sensitivity to speaker-specific speech patterns, tracking may increase. For code-switch density, if participants rely on acoustic cues, denser code-switching should yield stronger cortical tracking, reflected in increased model accuracy when acoustic predictors are added. Summary. The present study investigates how bilinguals may attune to speech patterns during a natural bilingual conversation containing code-switches. We test whether increasing familiarity with and adaptation to an interlocutor’s speech patterns may aid and dampen processing costs. By embracing naturalistic input, we aim to more accurately capture the neural dynamics underlying code-switch processing and the role of acoustic cues, with implications for theoretical models of bilingual language cognition.
Topic Areas: Multilingualism,