1. Introduction

The phenomenon of cross linguistic activation is widespread among second or multilingual speakers, with over half of the global population mastering two or more languages. The study focuses on the activation of second language vocabulary by second language learners during the process of recognizing native language vocabulary, aiming to reveal the coupling relationship between second language knowledge and native language memory, which is of great value for understanding the rules of bilingual activities.

2. Research background

There are different opinions on the issue of second language activation in the process of native language vocabulary recognition. Hoshino u0026 Thierry (2012) and Krogh (2022) suggest that second language does not automatically activate, while Khachatryan et al. (2016) found evidence of second language activation through EEG signals. Researchers have suggested that experimental tasks may affect second language activation. Krogh's (2022) vocabulary judgment task did not find second language activation, while Khachatryan et al.'s (2016) semantic relevance judgment task found second language activation. In addition, ERP technology can reveal the internal activities of the brain in processing language, which may differ from the results of behavioral experiments. The study will focus on the processing tasks of writing form and semantic concepts through two experiments, in order to gain a more comprehensive understanding of the activation state of second language in the process of native language vocabulary recognition.

3. Research methods

Introduced research methods, including experimental design and techniques. The experimental design is divided into two parts: Experiment 1 explores whether second language learners activate their second language when processing semantically unrelated writing forms, using a three factor design; Experiment 2 investigates whether second language learners activate their language when processing semantically related information, using a two factor design. In terms of experimental techniques, ERP technology was used to collect brain waves from subjects, and N400 component was used as the analysis index to explore cross linguistic cognitive activities.

Experiment 1: Writing Form Judgment Task

An experimental study was conducted on second language activation in the process of native language vocabulary recognition for Chinese Japanese learners. Experiment 1 involved 18 Chinese students with a Japanese proficiency level of N2 or above, who participated in a writing form judgment task. The experimental material includes 180 words, divided into Chinese and Japanese homophonic and non homophonic Chinese words, paired with 120 words to form semantically related and unrelated word pairs. The experimental procedure requires participants to determine whether the word count of the middle, left, and right structures is the same. The EEG data was recorded using a 62 Ag/AgCl electrode cap, controlled using Brain Vision Recorder software, and processed using Brain Vision Analyzer software. Analyzed the average wave amplitude of N400 components at eight electrode points, namely Cz, C1, C2, C3, C4, FCz, FC1, and FC2. The behavioral results showed that the accuracy of all conditions was above 90%, and reaction time analysis showed a significant main effect of the type of initiating word. The EEG results showed that the main effect of the correlation between the starting word and Chinese semantics was significant, but the interaction effect between the two was not significant. The experimental results indicate that when Chinese Japanese homophones are used as starting words, their Japanese semantics may not be activated, which may affect the second language activation of Japanese learners in the process of native language vocabulary recognition.

Experiment 2: Semantic Relevance Judgment Task

Experiment 2 involved 18 Japanese language learners from universities in Beijing, aged between 18 and 27, who were assigned a semantic relevance judgment task. The experimental materials, procedures, and data analysis methods are the same as Experiment 1. The behavioral results showed that the accuracy rates were all above 90%. Reaction time analysis showed that there were significant main effects on the types of starting words and Chinese semantic relevance, but the interaction between the two was not significant. ERP wave amplitude and EEG topography show a significant interaction effect between Chinese semantic relevance and the type of initiating words. When the starting word is a Chinese Japanese homophone with different meanings, the EEG differences caused by Chinese semantic correlation factors are not significant, possibly because the subjects activated their Japanese semantics when processing these words.

6. Discussion

This study explored the second language activation of Chinese Japanese learners during their native language vocabulary recognition process through behavioral experiments and event-related potential techniques. Research has found that when the starting word is a Chinese Japanese homophone with different meanings, participants exhibit significant changes in EEG effects, indicating that brain activity is affected when processing such vocabulary. The results of Experiment 2 showed that Japanese learners, when recognizing Chinese vocabulary, may activate Japanese vocabulary simultaneously if semantic processing is involved. This activation is particularly evident in semantic relevance judgment tasks, but not observed in vocabulary writing form judgment tasks. The study also found that the activation of second language vocabulary is influenced by experimental tasks, i.e. task dependent activation. In addition, the study supported the concept mediation model through EEG signal analysis and extended the model based on it, considering the influence of homonyms. The improved conceptual mediation model shows that when second language learners recognize homophonic words in their native language environment, they can automatically activate native language semantics and selectively activate second language semantics when processing semantic concepts.

7. Conclusion

Chinese Japanese learners exhibit significant EEG effects when using homophones with different meanings as starting words in their native language vocabulary recognition, demonstrating close cross linguistic connections between vocabulary. Only in the task of semantic relevance judgment, second language semantics are activated, revealing task dependency. Provide a new explanation for the controversy between language selectivity and non selectivity by comparing the activation patterns under experimental tasks, and confirm the phenomenon of mutual activation of vocabulary in different languages. The research results provide EEG experimental evidence for the activation of native to second language, which is of great significance for understanding the patterns of bilingual activities.