This paper takes up Bakhtin's dialogic perspective to explore the becoming of one Chinese international doctoral student's voices. We investigate how a single participant (from a wider study) assimilates the most transformative but "alien" voice of critical thinking in her supervision space by participating in dialogues with key speaking persons. When she assimilates this alien voice, the student also renovates her culturally enrooted and contradictory voice of respectful dependence. In this way, the student's voices develop and transform through a process of conflicts, struggles and reconciliations. This rich case study illustrates how a doctoral journey may be transformative cognitively and socio-culturally for the student as a speaking person--for her subjectivity. It also shows how this transformation is enabled not only by the supervisors' personal qualities but also through role modelling from peers: both kinds of relationships facilitate the student's assimilation of the most transformative voice in intercultural supervision.