With the rise in the number of international students (ISs) in many Asian universities, some recent research has investigated ISs' linguacultural experience in the new Asian educational hubs. Current research has shown that while English is used as the de facto academic lingua franca in many of these hubs, the local language of the host nation also plays critical roles in shaping ISs' social and academic interaction in multilingual Asian universities. Nevertheless, in most studies, ISs were generally positioned as a homogeneous group, dismissing the idiosyncrasies in their historical and sociocultural backgrounds. Informed by multilingualism [Kramsch, C. 2009. The "Multilingual Subject." Oxford, NY: Oxford University Press] and the theory of identity and investment (Darvin, R., and B. Norton. 2015. "Identity and a Model of Investment in Applied Linguistics." "Annual Review of Applied Linguistics" 35:36-56), this study adopted a qualitative case study methodology to investigate the multilingual development of a male, doctoral Vietnamese international student in a Taiwanese university where English and Chinese are the academic lingua francas. Data were collected through interviews, reflection journals, observation of social media posts, and relevant documents. Findings of the study illuminate how capital, ideologies, and identities worked in tandem to shape the participant's multilingual development in a Taiwanese university. These findings invite educators to challenge the hegemony of monolingualism and cultivate multilingual users in the globalized world.