Bi-dialectal, Bilingual, and Monolingual Experiences have Distinct Influences on Brain Development for Language

• In Event: Poster Session 13
  In Poster Session: PS 13 Topic - Language, Communication

Abstract

Question: How does bi-dialectal language experience influence children's emerging neural organization for language? It is now well established that bilingual experiences, such as those with Spanish and English, can have a fundamental impact on how the mind and brain process language. However, almost nothing is known about the effects of bi-dialectal experiences, such as those with standard American English and African American English, influence children’s neural organization for language processing.

Hypotheses: One of the core features of bi-dialectal language use is the variation in how sound units are pronounced, or phonology. Bilateral temporal regions, especially Superior Temporal Gyrus (STG), are classically associated with general and language-specific auditory processing while the posterior aspect of the left STG is especially critical for language (part of the Wernike’s region). We therefore hypothesized that bi-dialectal experiences within early life may influence the neural bases of children’s phonological processing, especially in the STG brain regions.

Method: We tested three age-matched groups of children (n=36, ages 7-10): African American English bi-dialectals, White American English monolinguals, and Spanish-English bilinguals with early bilingual exposure to English. The children completed a phonological awareness task that taps into children’s phonological processes critical for learning to read. During fNIRS neuroimaging, the children heard three words and decided which two of those words matched in the initial sound (cat-cab-dog).

Results: Standard measures of language and literacy in English revealed that the three groups were similar in English vocabulary, phonological awareness, and reading proficiency. There were also no group differences in neuroimaging task performance. Nevertheless, in this ability-matched group of speakers, bi-dialectal children showed stronger bilateral temporal activation, including stronger left pSTG activation as compared to monolingual and bilingual speakers (p < 0.05). In contrast, bilingual children showed stronger and more wide-spread right hemisphere activation, whereas monolinguals had stronger occipital activation (p < 0.05). The finding of greater bilateral temporal activation in bi-dialectals is consistent with our hypotheses, while the findings for monolinguals and bilinguals are also logical. The greater occipital activation in the monolinguals is consistent with prior evidence that learning to read prompts children to invoke visual word representations to make decisions about auditory language sounds. The bilateral activation in the bilinguals is consistent with the idea that the two hemispheres are more involved in dual than single language processing. Remarkably, the bi-dialectals appear to be different from both the monolingual and bilingual groups. The greater temporal activation in bi-dialectals puts forth a tantalizing possibility that bi-dialectal experiences with an increased diversity in phonological forms for similar lexical items influences how children process language sounds and the developing neural systems for phonological processing. In sum, the findings reveal how different types of language experiences, monolingual, bilingual, and bi-dialectal, can have distinct influences on brain development for language.

Authors

• Nia Nickerson, University of Michigan - Ann Arbor
  Presenting Author

• Chi-Lin Yu, University of Michigan - Ann Arbor
  Non-Presenting Author

• Rachel Eggleston, University of Michigan - Ann Arbor
  Non-Presenting Author

• Rebecca Marks, University of Michigan - Ann Arbor
  Non-Presenting Author

• Zachary Karas, University of Michigan
  Non-Presenting Author

• Xin Sun, University of British Columbia (UBC)
  Non-Presenting Author

• Kehui Zhang, University of Michigan
  Non-Presenting Author

• Xiaosu Hu, University of Michigan
  Non-Presenting Author

• Nicole Gardner-Neblett, University of Michigan - Ann Arbor
  Non-Presenting Author

• Teresa Satterfield, University of Michigan
  Non-Presenting Author

• Ioulia Kovelman, University of Michigan - Ann Arbor
  Non-Presenting Author