The Impact of Prenatal Language Environment on Newborns: A Meta-Analysis of fNIRS Studies

This meta-analysis synthesizes findings from functional Near-Infrared Spectroscopy (fNIRS) studies on neonates to investigate the neural mechanisms underlying language acquisition. The review focuses on studies that explore how prenatal language exposure might influence the development of the auditory system in fetuses by comparing the native language to a non-native language or a non-language stimulus. A total of nine peer-reviewed studies were selected for the literature review, and three studies were included in the meta-analysis based on predefined inclusion criteria. During the meta-analysis, MATLAB and JASP were used to combine and analyze the results. The findings revealed that the left temporal cortex was active during forward speech, suggesting early lateralization of language processing. Differences in neural activation were observed when neonates were exposed to languages of different rhythmic classes and backward speech. The results of this meta-analysis contribute to our understanding of how prenatal experiences influence language acquisition and auditory development.