Chapter 1 Introduction 1.1 Research background 1.2 Research purposes and questions 1.3 Research significance Chapter 2 Epistemological Foundations 2.1 Acculturation studies 2.2 Schumann's Acculturation Model 2.3 Measurement of acculturation 2.4 Measurement of language proficiency 2.5 Relationships between acculturation and second language proficiency 2.6 Relationships between acculturation and foreign language proficiency 2.7 Chinese immigrants in studies of acculturation in relation to ESL proficiency 2.8 Chinese English learners in studies of acculturation in relation to EFL proficiency Chapter 3 Methodology 3.1 Research objectives 3.2 Research design Chapter 4 Results and Discussion 4.1 Validity and reliability analysis of instruments 4.2 Question One: Demographic variables' impact on EFL learners' acculturation 4.3 Question Two: Accuhuration's role in English proficiency (EP) prediction along with other demographic factors 4.4 Question Three: Language proficiency's reactive role to acculturation, social distance and psychological distance 4.5 Summary Chapter 5 Conclusion 5.1 Pedagogical implications of acculturation studies 5.2 Limitations and suggestions Appendices Appendix 1 EFL learners' acculturation measurement questionnaire Appendix 2 Self-assessment of English proficiency questionnaire References Acknowledgements