1. Introduction

The importance of vocabulary in second language learning was emphasized, and it was pointed out that the main goals of Chinese English learners in university are to expand their vocabulary and improve their comprehension and expression abilities. The research background mentions that most second language vocabulary is acquired through reading, but how to effectively acquire vocabulary through reading is still a controversial issue. This study aims to explore how Chinese English learners acquire new vocabulary through story reading under the assumption of contextual variation in new word learning.

2. Literature review

This article summarizes two ways of acquiring second language vocabulary through incidental reading: multiple readings and multiple readings, and their impact on vocabulary acquisition. Bolger et al. (2008) proposed that changing contexts (multiple readings) are more effective in promoting vocabulary learning than repetitive contexts (multiple readings), and verified this hypothesis through experiments. Subsequent research explored the relationship between contextual variability and vocabulary acquisition, and found that the frequency of target word exposure and the richness of contextual information have a positive impact on vocabulary acquisition. However, the research results on the influence of contextual variability are inconsistent. There are three main problems with existing research: 1) Most studies use isolated sentences as materials and lack examination of story context; 2) Mainly focusing on immediate effects, lacking attention to delayed effects; 3) Isolated examination of contextual factors, lacking integration with individual learner factors. This study aims to investigate the impact of contextual variability on second language vocabulary acquisition and explore the role of learners' story comprehension ability, in order to provide richer evidence for the contextual variability hypothesis.

3. Experimental design

This chapter introduces a study aimed at exploring the impact of story reading on incidental acquisition of second language vocabulary. The research subjects are 52 first-year non English major college students with nearly 10 years of English learning experience. Before the experiment, participants were screened through vocabulary testing. The reading material consists of 36 English short stories, each containing a target word that appears in the form of false words in the story to avoid pre recognition by the subjects. The length, difficulty, and vocabulary usage of the story have been carefully designed to ensure that most of the vocabulary is frequently used. The experiment adopts a Latin square design, controls for contextual variables, and requires participants to read three different stories containing the same target word or repeat the same story three times. The experimental process used E-prime 2.0 software to present the story sentence by sentence, and the subjects controlled their reading progress through buttons. After reading, participants completed story comprehension questions and underwent vocabulary tests immediately and three weeks after the experiment, including semantic generation and cloze tests.

4. Results

Statistical analysis was conducted using R software, with a significance level of α=0.05, to investigate the performance of participants in semantic generation tasks and cloze tasks. In semantic generation tasks, the learning performance of subjects in changing contexts is better than in repetitive contexts, and this effect is not affected by testing time or the subjects' ability to understand stories. In cloze test tasks, test time has a significant impact on learning outcomes, while the main effect edges of context and story comprehension ability are significant. There is a significant three-way interaction effect among the three, indicating that in real-time testing, the influence of context on vocabulary learning is moderated by story comprehension ability, while in delayed testing, the learning effect under changing context is always better than that under repeated context. In addition, there is a significant bidirectional interaction effect between context and story comprehension ability.

5. Discussion

Explored the impact of reading materials in different contexts on incidental acquisition of second language vocabulary by learners. Research has found that changing context (reading multiple articles from different materials) has a significant advantage in vocabulary learning effectiveness in semantic generation tasks, and is not affected by test time or learners' story comprehension ability. However, in cloze tasks, there is an interactive effect between the role of context, testing time, and learners' ability to understand stories. The impact of changing and repeating contexts on vocabulary learning depends on the type of testing task and the learner's comprehension ability. Changing contexts can help learners grasp explicit knowledge of vocabulary, while repetitive contexts may be more advantageous for context based vocabulary knowledge acquisition in certain situations. The study emphasizes the importance of changing contexts and learners' reading comprehension abilities in vocabulary learning, pointing out that to achieve optimal learning outcomes, it is necessary to simultaneously leverage the strengths of both.

6. Conclusion

This study is based on the hypothesis of contextual variation and explores the incidental acquisition effect of second language vocabulary by Chinese learners in changing and repetitive contexts, as well as its correlation with story comprehension ability, through a foreign language story reading experiment. Research has found that changing context has a significant advantage on learners' de contextualized explicit vocabulary knowledge learning, while its impact on learners' ability to access vocabulary knowledge under cue prompts is more complex, moderated by story comprehension ability and test time. The research findings support the applicability of the contextual variation hypothesis in second language vocabulary acquisition and reveal the interaction between changing contexts and individual learner factors. For foreign language beginners, it is recommended to acquire vocabulary through multiple readings to promote the formation of explicit knowledge and the mapping of word form to semantics. To achieve long-term vocabulary learning outcomes, the dual effects of changing contexts and comprehension abilities should be considered simultaneously. Teachers should create favorable vocabulary learning conditions for learners from both teaching methods and material development.