This article presents the findings of a corpus-based study of the use of English vis-à-vis Cantonese and Putonghua in Hong Kong's Legislative Council in the past four decades. The objective of the study was to track the changing fortunes of the three languages in a key government institution during a period of unprecedented political, economic and social change. This was accomplished by analysing a 91-million-word corpus of Council proceedings derived from "Hong Kong Hansard," which is the verbatim record of Council meetings. For the greater part of the colonial era (1842-1997), English was the sole medium of communication in the chamber. It was only in 1972 that Cantonese-speaking members were permitted to use the city's majority language in Council debates. In that year every speech was in English. Forty years later, only 0.38% of the addresses were in the colonial language, the overwhelming majority being in Cantonese (99.45%), with only a handful in Putonghua. This article describes and discusses the rise of Cantonese and the concomitant demise of English since the early 1970s, with a particular focus on the transitional 1990s, and speculates on the roles of Cantonese and Putonghua in the legislature in the years ahead.