Asian Journal of Education and Social Studies

Improving proficiency in Portuguese is critical for elementary students’ learning in the multilingual context of Timor-Leste. This quantitative study aims to understand how multilingualism affects Portuguese language proficiency among Grade 5 and Grade 6 students. The sample of this study was 175 students from elementary schools in Baucau, Timor-Leste. The experiment was conducted according to the interdependence and threshold hypotheses introduced by Cummins using a validated 25-item Portuguese Language Proficiency Test and a linguistic background questionnaire. The results of the reliability test indicated that Cronbach's alpha was 0.742, and the content validity index (CVI) was 1.00, indicating satisfactory correspondence with the national standards. The results of the statistical descriptive analysis of the Portuguese proficiency test demonstrate that students’ vocabulary (M = 7.58) had a high mean score, while grammar and writing (M = 6.05) had a low mean score, which showed an unequal level of language skills. The regression analysis result shows that being multilingual is a strong predictor of Portuguese proficiency, with a moderately positive correlation (t = 7.130, p = 0.05, b = 0.477, r = 0.477, p = 0.01). It concludes that multilingual competence is a significant factor in enhancing Portuguese language proficiency among elementary school students in Timor-Leste. The study highlights the necessity to increase the efforts of mother-tongue-based multilingual education (MTB-MLE) through teacher training by using culturally competent textbooks and language-supportive policies in Timor-Leste.