This article investigates the integration of bilingual literacy through thematic instruction at a specialized bilingual primary school in Ukraine. The study addresses the pedagogical challenges inherent in "artificial bilingualism," where learners navigate a complex triad: Russian as the home language (L1), Ukrainian as the primary language of instruction (L2), and English as a foreign language (L3). Central to this research is the Integrated Literacy Development Approach (ILDA), which utilizes Flavell’s metacognitive framework and Vygotsky’s sociocultural theory to bridge linguistic gaps through structured scaffolding. The pedagogical design combines thematic content units, such as "Transport" and "Food," with multimodal tools including bilingual concept maps and "grammar rulers." These metacognitive schemes enable Grade 1 students (ages 6–7) to categorize vocabulary and visualize syntactic structures across languages. The methodology employs a mixed-methods approach, utilizing classroom observations, semi-structured interviews, and statistical analysis via Fisher’s φ-criterion. Results indicate a significant improvement in bilingual proficiency, with successful sentence construction rising from 40.0% to 86.7% (p < 0.01) over two semesters. Qualitative data from teacher interviews and field notes reveal that visual scaffolds facilitate cross-linguistic transfer and enhance self-correction capabilities. The study concludes that intentional metacognitive scaffolding reduces cognitive load and prevents linguistic interference. These findings offer critical implications for curriculum design and teacher training in international contexts where students must achieve academic literacy in a foreign tongue while simultaneously developing their national language proficiency.