This study investigated K-12 level EFL learners' written development through syntactic and lexical complexity measures in light of two teaching methodologies: CLIL and non-CLIL. The results indicated that despite the higher amount of exposure in the CLIL setting, no significant differences were found between the two groups, both of which had significant gains in lexical diversity after a semester of instruction.
Content integrated language learning (CLIL) through English as the medium of instruction (EMI) has not been well-established in Turkey except a few private K-12 schools in the Turkish EFL community and has only been researched in public or private tertiary contexts (Bozdogan & Karlidag, 2013). Given the limited number of studies from secondary school contexts, Genesee & Lindholm-Leary (2013) indicated that CLIL and other forms of immersion have been beneficial in terms of successful language learning, as well as academic subjects and intercultural competence. Motivated by its benefits, yet its limited implementation in Turkey, this study aims to investigate the effects of CLIL on written L2 syntactic and lexical complexity development in the Turkish K-12 context over a semester compared to an intensive English programmed school. The data analyzed were collected from two schools: an intact class of ninth graders studying at a science, technology, engineering, and mathematics (STEM) enhanced (i.e. a form of CLIL in the Turkish K-12 context) school and a private secondary school where English is instructed through an intensive integrated skills (IIS) curriculum. The participants took an initial proficiency test of Elicited Imitation (Ortega et al., 1999), the results of which were used as covariant coefficients in the statistical tests. Having a quasi-experimental design, this study includes a pre and post computer-based timed written task to determine participants' development in L2 writing through measures of written syntactic and lexical complexity over a semester. This data set was first transcribed into CLAN (MacWhinney, 2000) following CHAT conventions to determine CAF measures. The results of these analyses were later used in inferential statistical tests as dependent variables. The study is anticipated to shed light on different areas of L2 written performance in a way to clarify what type of benefits learners might get through the two different teaching methodologies.
