The study employs a case study approach to examine the impact of educational backgrounds on nine Hong Kong tertiary students' English and Cantonese language practices and identifications as native speakers of English and Cantonese. The study employed both survey and interview data to probe the participants' English and Cantonese language use at home, school, and with peers/friends. Leung, Harris, and Rampton's (1997, The idealized native speaker, reified ethnicities, and classroom realities. "TESOL Quarterly" 31(3). 543-560) framework of language affiliation, language expertise, and inheritance was used to examine the construction of a native language identity in a multilingual setting. The study found that educational background--and particularly international school experience in contrast to local government school education--had an impact on the participants' English language usage at home and with peers, and also affected their language expertise in Cantonese. English language use at school also impacted their identifications as native speakers of both Cantonese and English, with Cantonese being viewed largely as native language based on inheritance while English was being defined as native based on their language expertise, affiliation and use, particularly in contrast to their expertise in, affiliation with, and use of Cantonese.