This study delves into the intricate dynamics of trilingual education, focusing primarily on Vietnamese students majoring in French and simultaneously learning English as a foreign language. Themes emerging from the semi-structured interviews encompass dual linguistic socialization, constructing knowledge through French while learning English, perceived insufficiencies in real-world English exposure, language interference, and the profound role Vietnamese plays in third language acquisition. Additionally, motivational aspects, perceived hierarchies of languages, cultural isolation, cognitive space struggles, institutional prioritizations, and the interplay of cultural identities come to the fore. Utilizing the frameworks of Sociocultural Theory, Constructivist Theory, and Input Hypothesis, the research contextualizes these themes, uncovering the challenges and enrichments of this trilingual journey. The study's implications suggest the necessity for tailored pedagogical strategies and support systems for trilingual learners. This work contributes significantly to the growing discourse on multilingual education, providing educators, policymakers, and learners with valuable perspectives.