This research paper investigates the effects of integrating multiliteracies in a Content and Language Integrated Learning (CLIL) programme on language development and content understanding among preschoolers in an urban city of Greece. The case study focuses on early literacy skills, spoken discourse and vocabulary. The research questions, which guided the study, aims to explore the impact of multiliteracies integration in the CLIL programme on early literacy skills and to understand how it influences spoken discourse, and vocabulary skills among preschoolers. A convenient sampling method was employed, and the study was conducted during the school year 2022-2023 in a preschool involving 40 preschoolers. The programme followed a structured process involving experience, conceptualization, critical thinking and real-life application. Data collection methods included pre-tests, post-tests and classroom observations. The findings revealed the positive effects of integrating multiliteracies in the CLIL programme on their language skills. The preschoolers saw an observable enhancement in fluency, vocabulary usage and oral communication abilities. Observations highlighted increased language engagement, oral discourse production, interaction and collaboration, multimodal learning experiences, motivation and engagement and the development of critical thinking skills, emphasizing the effectiveness of the CLIL programme in fostering oral communication skills and creating an immersive educational environment.