My dissertation examines how the introduction of Cantonese as the co-official language (alongside English) in Hong Kong courts since 1997 produces far-reaching implications to the implementation of the common law there. I hypothesize that (1) the recent availability of Cantonese in Hong Kong courts empowers the locals in their interaction with the legal system by opening up new performative possibilities inherent in the mother tongue; (2) the new court language brings the ethos of the legal system closer to local values and beliefs than it was in the past, when English was the sole official language. Comparative ethnography and in-depth interviews will be conducted to assess the changes I anticipate. The present availability of both Cantonese and English trials provides an ideal "natural" setting for the study. Various aspects of courtroom interaction (assumptions and norms shared by speaker and hearer during interaction, narrative plot, linguistic competence, key, bodily acts, speech style and variation) will be observed in the process.