AbstractThe purpose of this study is to investigate the characteristics of imagined communities, identities, and investment, as well as the linguistic behaviours among high and low proficiency ESL learners. The data of this qualitative study were collected through indepth interviews and written narratives from 12 high-proficiency undergraduate ESL learners and 10 low-proficiency undergraduate ESL learners, who were selected based on the learners_ Malaysian University English Test (MUET) result. The data were analysed through thematic analysis, to generate themes and patterns related to the participants_ imagined communities, identities, investment, and linguistic behaviours. The findings revealed that high-proficiency learners_ imagined communities, identities and investment are reflective of their professional aspirations and career success, global communication, travel, and cultural adaptation, educational influence and inspiration, as well as their social and peer influence. In contrast, lo.....