As an extension of Kang et al. (2021), the current project further analysed 41 L1 Korean IELTS test-takers’ performance data for writing features and comprehensively examined their association with IELTS proficiency levels and their linguistic progression in relation to their background. Additionally, by using previously analysed speaking features, the study examined how they could distinguish IELTS speaking proficiency.
Once participants completed the pre-test survey, they took the pre-arranged official IELTS test. Participants’ hours of study and target language use information was collected weekly. The post-survey was conducted at the end of the three-month period after the official IELTS post-test. The individual long-run speaking responses from the pre- and post- tests were used for speech analysis. Forty-one (41) participants’ writing samples were analysed for writing features (i.e., discourse complexity, lexical sophistication, lexical diversity, grammatical complexity, essay length).
The results showed that speech rate, grammatical complexity, the use of L1 words, intonation level-tone choice, and segmental errors were significant predictors of IELTS speaking proficiency scores with R2 = 40–60%. As proficiency improved, IELTS test-takers spoke faster but their grammatical structure became less complex. As for writing, essay length and lexical sophistication contributed significantly to the writing proficiency scores (R2 = 35–46%), and participants’ proficiency affected their writing improvement most consistently and significantly.
Findings can inform the development of the IELTS band score descriptors and make contributions to the fields of second language (L2) testing and second language acquisition (SLA) by offering concrete evidence to assist understanding of the relationship between learning outcomes and learner backgrounds.