Effect of second language exposure on brain activity for language processing among preschoolers

Area of Science:

• Neuroscience
• Developmental Psychology
• Linguistics

Background:

• Early childhood bilingualism research is crucial for understanding cognitive development.
• Investigating neural correlates of second language acquisition in preschoolers provides insights into brain plasticity.
• Limited research exists on the neural processing of multiple languages in very young children.

Purpose of the Study:

• To examine brain activity in preschoolers (3-5 years old) in response to native, second, and foreign language speech.
• To compare neural responses between younger and older preschoolers with varying English exposure durations.
• To explore the influence of second language exposure on brain activity in early childhood.

Main Methods:

• Near-infrared spectroscopy (NIRS) was used to measure brain activity.
• Participants listened to connected speech in Japanese (L1), English (L2), and Chinese (foreign language).
• Brain activity in bilateral frontal regions was analyzed based on age and English exposure duration.

Main Results:

• Older preschoolers (approx. 2 years English exposure) exhibited higher bilateral frontal activity for Japanese and English compared to Chinese speech.
• Younger preschoolers (approx. 1 year English exposure) showed less distinct patterns.
• The observed pattern in older preschoolers resembled that of adults with several years of English learning.

Conclusions:

• Second language exposure significantly affects preschoolers' brain activity in response to language stimuli.
• Bilateral frontal regions are involved in processing familiar and newly acquired languages in early development.
• These findings highlight the neuroplasticity of the preschooler brain in response to linguistic input.