Title Page
Abstract
Contents
I. Introduction 11
1.1. Background of the Study 13
1.2. Purpose of the Study 15
1.3. Research Questions 16
II. Literature Review 17
2.1. Theoretical Background 17
2.2. Previous Study 20
2.2.1. The Concept of Critical Period 20
2.2.2. The Supporting Side by Foreign Scholars 24
2.2.3. The Opposite Frameworks on the Critical Period Hypothesis 26
2.2.4. The Psychology Factor Related to the Age Onset on Second Language Acquisition 36
2.2.5. The Related Views from Experts on the Optimal Age for Second Language Learning 39
2.2.6. The Discussion on China's English Education Policy 52
2.3. Research Hypothesis 59
2.4. Statement of the Study 59
2.5. Significance of the Study 62
III. Methodology 65
3.1. Participants 65
3.2. Instruments 67
3.2.1. Questionnaire 67
3.2.2. CET-4 Test 68
3.2.3. Duolinguo Oral Test 69
3.2.4. Interview 70
3.3. Research Design 71
3.3.1. The Selection of Study Type 71
3.3.2. The Definition of Age of Onset 76
3.3.3. The Definition of Achievement 78
3.3.4. The Necessity of Interviews 83
3.4. Research Procedure 85
3.5. Data Collection and Analysis 88
IV. Results and Discussions 92
4.1. General Findings on Subjects 93
4.2. Results 94
4.2.1. Does the Age of the Chinese EFL Learner Impact the English Outcomes (including pronunciation; vocabulary)? 94
4.2.2. What Age is the Best Age to Learn English for Chinese EFL learners? 105
4.2.3. In Addition to age factor, What can be the Possible Influence Factors in English Achievements? 111
4.2.4. Interview Results 113
4.3. Discussion 120
4.3.1. The Powerful Influence of Acquisition Age 120
4.3.2. The Influence of Age on Pronunciation 123
4.3.3. Potential factors influencing Chinese speakers' pronunciation 124
4.3.4. Grammar and Accent 126
4.3.5. Multiple Critical Period Effects Proposal 128
4.3.6. The Comparative of Gender on Second Language Acquisition 129
V. Conclusion 136
5.1. Summary 136
5.2. Implication 138
5.3. Suggestions for further studies 147
5.4. Limitation 150
References 152
Appendices 167
Appendix I. Consent Form 167
Appendix II. Basic Information of Participants - Survey Instrument 169
Appendix III. Questionnaire for College Students- English Learning Performance 170
국문요약 172
TABLE 1. The fundamental information of the participants 67
TABLE 2. Demographic data of participants 93
TABLE 3. Description of participants on a five-point scale 96
TABLE 4. Regression Model of Speech 104
TABLE 5. ANOVA for both groups' CET score findings 106
TABLE 6. ANOVA for both groups' reading and writing outcomes 107
TABLE 7. ANOVA for both groups' vocabulary and grammar findings 109
Figure 1. Deductive analysis of interview results 114