Adinda Azzahroh Salsabilla Alimi Adinda Azzahroh Salsabilla Alimi, Fera Zasrianita, Andriadi
This study aimed to explore the influence of local language use on vocabulary knowledge and speaking fluency among English for Young Learners (EFYL) at LKP Ambassador Bengkulu. A qualitative case study design was employed to obtain an in-depth understanding of how local language supports students' vocabulary development, speaking fluency, and confidence in a non-formal English learning environment. The participants consisted of students enrolled in the EFYL program. Data were collected through classroom observations, semi-structured interviews, and documentation, and were analyzed using qualitative case study procedures through data reduction, data display, and conclusion drawing. The findings revealed that the strategic use of the local language facilitated students' understanding of unfamiliar vocabulary, strengthened vocabulary retention, and increased their confidence during English speaking activities. Students with broader and more accurate vocabulary knowledge demonstrated greater speaking fluency, expressed ideas more clearly, and communicated with fewer pauses and hesitations. The study also identified that vocabulary breadth, vocabulary variation, contextual accuracy, understanding of word meanings, and vocabulary retrieval ability were the main components contributing to speaking fluency. However, vocabulary mastery alone did not automatically guarantee fluent speech, as cognitive processing, speaking experience, and psychological factors such as confidence and anxiety also influenced oral performance. The study concludes that balanced use of the local language, combined with meaningful vocabulary instruction, repeated communicative practice, and supportive classroom interaction, effectively promotes vocabulary development and speaking fluency among young learners in non-formal English education