This paper aims to investigate the everyday language use of non-Cantonese native speakers who work in Hong Kong from the perspective of sociolinguistics. The three languages, namely Cantonese, Putonghua and English, will be examined closely in terms of their frequency of use in both workplaces and non-workplaces. By comparing the mean scores and related variables, this study further discusses and explains the phenomena of language shift of non-Cantonese native speakers.