From an ecolinguistic perspective, this paper investigates the connection between multilingual environments and Cantonese English identity in the Greater Bay Area through questionnaires and interviews. The findings reveal the following: (1) Affective and behavioural indicators of self-identity varied significantly among different majors, as well as among different environmental groups; (2) Students' social identity remained unaffected by their majors but exhibited significant differences among groups; (3) Cantonese English self-identity and social identity of the students (except for Hong Kong and Macau students) with multilingual backgrounds demonstrated a high correlation. In brief, the identity ratios were as follows: English majors > non-English majors; Hong Kong-Macao students > Pearl River Delta students > New Arrivals. These results suggest and confirm the symbiotic and coordinative interaction between language and environment. Different environments impact learners' cognitive psychology, leading to varying degrees of self-identity in Cantonese English. In other words, the environment determines language, and conversely, language, together with its intralingual environment, imbued with historical and cultural values, emotions, and identity, plays a behavioural role in influencing cognitive psychology, society, and even nature.