Developing sentence complexity in students' written texts with sentence-based practice

The multifaceted nature of writing, encompassing cognitive, linguistic, and contextual aspects, presents challenges for learners striving to produce high-quality written work. Linguistic proficiency demonstrated in a text is the fundamental aspect among the interrelated elements that contribute to the overall quality of students' written products. Studies in second-language writing consistently indicate that well-crafted compositions are associated with linguistic sophistication and diversity, which can be enhanced through explicit teaching. This quasi-experimental research investigates the effectiveness of sentence-based practice in enhancing sentence complexity in second-language writing. The literature provides research endeavors on various sentence-based practices that have been proposed, such as sentence combining and translation, to support learners in improving sentence complexity. However, such practices need to be reconsidered since prior investigations in the specific context of a preparatory department at a private university in Turkey have proven insufficient for students to transfer complex structures, particularly subordination, into their written performance. Thus, this study proposes an alternative practice that integrates translation into traditional sentence-combining tasks to enhance the density of subordination in students' written output. Additionally, the study explores the correlation between the density of subordination and the quality scores assigned by raters at the institution. With this purpose, an intervention and a placebo were administered to two intact CEFR level B2 upper-intermediate classes over fourteen weeks. The data collected from the writing exams before, during, and after the treatment provided data for analysis. Subordination density in participants' compositions was calculated, and overall writing scores were evaluated using the institution's and IELTS writing rubrics. The subordination density scores between and within the groups were compared using repeated measures ANOVA. The results indicated that sentence-combining merged with translation promotes students' ability to write complex sentences with increased subordination. Furthermore, the comparison of post-test results revealed a significant difference in writing performances between the treatment and control groups, irrespective of the rubric used. Notably, overall writing scores assessed by the IELTS rubric positively correlated with the subordination density of participants' written products. Finally, based on inferences drawn from the findings of this study, potential implications and applications were identified and summarized to conclude the present study.