Yabancı dil olarak İngilizce öğrenen Türk öğrencilerinin tartışma metinlerinin yazılı karmaşıklık gelişim düzeyleri

This study aimed (a) to identify written grammatical complexity (i.e., syntactic complexity) stage(s) and grammatical functions of undergraduate Turkish EFL students based on Biber et al.'s (2011) framework for grammatical complexity developmental stages, and (b) to investigate the effect of topic on students' grammatical complexities and functions. The data were collected from 60 argumentative essays on three different topics written by second-year students studying at a foundation university in Turkey. The data were qualitatively coded through Ellis' (2008) form analysis, in which all the instances of complex forms were identified and designated to the appropriate stages and grammatical functions (adverbial, complement, and noun modifier). Frequencies of complex forms and functions were calculated for the whole group and for each topic separately. Kruskal-Wallis test was conducted to see the topic effect on students' grammatical complexity stages and grammatical functions. The results of the study pointed out that the majority of grammatical complexity features of L2 learners were in Stage 2 and Stage 3. The findings also showed that topic affected grammatical complexities in Stage 2, Stage 4, and Stage 5. Regarding the grammatical functions, topic affected the use of noun modifiers, but not adverbials and complements. Based on the findings, this study is in line with previous studies: L2 learners' texts demonstrate basic level phrasal modification and reflect features of conversation more than features of academic writing. To promote complexity features of academic writing, L2 writing instruction should align with current findings regarding register differences. Keywords: syntactic complexity, grammatical complexity, phrasal complexity, L2 academic writing, register differences