Due to globalisation and rapid technological change, today's educators need to help students develop multi-literacy competencies to enable them to function successfully in our culturally and linguistically diverse (CLD) and increasingly connected global and digital society. A qualitative, longitudinal case study attempted to uncover the multi-literacies development of one young trilingual child (Korean, English, French), Julie, between the ages of six and eight within a multilingual context. As a teacher-and-researcher who initiated and designed a multi-literacies curriculum for young CLD children in informal learning contexts, in this article, I seek to explore how Julie developed and utilised multimodal modes in and out of literacy curriculum in Montreal, Canada. Drawing on Vygotskian sociocultural theory, findings suggested that: (1) Julie developed her persuasive voices and inner voices through appropriating authoritative voices in a playful manner; and (2) Julie and her family recognised and developed the multi-literacies-related funds of knowledge via informal learning contexts that were not part of the formal curriculum within Julie's formal learning spaces. The study contributes to the benefits of encouraging informal learning that could challenge and support multi-literacies curricular in formal learning contexts. The article concludes with considerations of implications for future work.