1. Introduction

This article introduces the fundamental role of brain neural mechanisms in language learning and use, explores the importance of the neural mechanisms of second language processing in foreign language research and neurolinguistics, and highlights the key to the development of bilingual theory. The chapter also discusses the challenges faced by bilinguals in storing, extracting, processing, and controlling information in two languages. In addition, two main views on whether the neural mechanisms of native and second language representation are independent were outlined: the integrative view and the independent view, as well as the empirical research support for these two views.

2. Research background

The difficulties faced in the study of neural mechanisms of native and second language representation for bilinguals were discussed, including differences in native and second language proficiency, language feature differences, bilingual cross interaction effects, and the influence of language control systems. In addition, other influencing factors such as individual differences among bilinguals, language acquisition age, and acquisition context were also pointed out. To overcome these difficulties, this study used functional near-infrared imaging technology (fNIRS) to investigate whether bilingual newborns have integrated or independent features in their language representation at birth. The study found that selecting bilingual newborns can effectively avoid proficiency differences by using passive speech processing tasks to reduce the influence of language features and language control systems. At the same time, newborns are less affected by bilingual cross interaction effects in language processing tasks.

3. Method

The methodology section provides a detailed description of the neural mechanisms underlying language representation in bilingual newborns. The research subjects are 90 healthy full-term newborns who grew up in a bilingual Chinese English environment and whose parents have signed informed consent forms. The experimental materials selected declarative sentences with minimal changes in acoustic characteristics, which were pronounced by two female native speakers to ensure emotional neutrality of the speech materials. The experimental design is conducted in a soundproof room, where newborns receive speech stimuli in both Chinese and English while awake or in light sleep. Each language block contains 20 segments of 15 second speech, with a 5-minute break between the blocks. Near infrared data collection uses the NIRScout 1624 system to record brain activity. Data preprocessing and analysis were performed using nirsLAB and RStudio software to calculate the relative concentration changes of oxygenated hemoglobin, followed by statistical analysis. Finally, BrainNet Viewer software was used to display the brain connectivity results.

4. Results

Through paired sample t-test, it was found that Chinese speech induced stronger brain functional connections than English speech on 27 channels, forming a neural network centered around the prefrontal cortex; On the 19 channels, English speech induces stronger connections, forming a network centered around the superior temporal gyrus. Figure 1 shows the brightness and thickness of brain functional connections, as well as the location of brain regions represented by the node colors of near-infrared channels.

5. Discussion

This chapter discusses the neural mechanisms of language representation in bilingual newborns, and uses near-infrared technology to study the neural perceptual responses of Chinese English bilingual newborns on the day of birth to Chinese and English speech. Research has found that the neural networks in the left hemisphere of bilingual newborns exhibit different levels of functional connectivity in Chinese and English speech perception. The network connectivity in the inferior frontal gyrus is higher in Chinese speech perception, while the network connectivity in the superior temporal gyrus is higher in English speech perception. This result supports the view that the neural mechanisms of bilingual language representation are relatively independent and indicates that this independence is a congenital feature. The inferior frontal gyrus and superior temporal gyrus play different roles in language processing. The inferior frontal gyrus is related to oral production, while the superior temporal gyrus is related to language comprehension and phonological perception. The study also proposed two possible explanations: the influence of speech features and the influence of silent imitation reactions.

6. Conclusion

This chapter summarizes the research results on the neural mechanisms of language representation in bilingual newborns, pointing out that bilingual newborns activate independent neural networks when processing different languages, supporting the independence of language representation, and emphasizing the key roles of the inferior frontal and temporal gyrus in the early stages of language development. At the same time, the limitations of using newborns as experimental subjects were pointed out, and future research needs to explore the neural mechanisms of bilinguals under different language processing tasks.