Bilingual exposure enhances left IFG specialization for language in children

• Published in: Bilingualism (Cambridge, England) Vol. 22; no. 4; pp. 783 - 801
• Main Authors: Arredondo, Maria M, Hu, Xiao-Su, Seifert, Erica, Satterfield, Teresa, Kovelman, Ioulia
• Format: Journal Article
• Language: English
• Published: England Cambridge University Press 01.08.2019
• Subjects: Adults; Bilingualism; Brain; Brain Hemisphere Functions; Brain research; Children; Children & youth; English language; Grammatical agreement; Grammaticality; Inflection (Morphology); Judgment; Language; Language acquisition; Language Proficiency; Lateralization; Linguistic competence; Linguistics; Medical imaging; Monolingualism; Morphosyntax; Multilingualism; Semantics; Spanish language; Syntactic processing; Tense; Verbs; Young Children; Ann Arbor Michigan; United States > US; fNIRS; inferior frontal gyrus; morphology; children; grammaticality; syntax; language; proficiency; bilingualism; neuroimaging
• ISSN: 1366-7289; 1469-1841
• DOI: 10.1017/S1366728918000512

Language acquisition is characterized by progressive use of inflectional morphology marking verb tense and agreement. Linguistic milestones are also linked to left-brain lateralization for language specialization. We used neuroimaging (fNIRS) to investigate how bilingual exposure influences children's cortical organization for processing morpho-syntax. In Study 1, monolinguals and bilinguals ( =39) completed a grammaticality judgment task that included English sentences with violations in earlier- (verb agreement) and later-acquired (verb tense/agreement) structures. Groups showed similar performance and greater activation in left inferior frontal region (IFG) for later- than earlier-acquired conditions. Bilinguals showed stronger and more restricted left IFG activation. In Study 2, bilinguals completed a comparable Spanish task revealing patterns of left IFG activation similar to English. Taken together, the findings suggest that bilinguals with linguistic competence at parity with monolingual counterparts have a higher degree of cortical specialization for language, likely a result of enriched linguistic experiences.