The effects of content based instruction on the students' academic success in vocational foreign language (English) classes

This study aims to determine the extent of the effects of a Vocational English Programme based on Theme-based teaching model of The Content Based Instruction the students' academic success in their foreign language skills (reading-writing) and knowledge in the related subject area. In this research, pretest-posttest control group design, which is one of the true experimental designs, was used as the method of the study. The participants of the study are the second grade students in the Computer Programming Department in the Ahi Evran University Vocational Schools. The experimental group consists of the students in Central Vocational School and the control group includes the students in Akpınar and Çiçekdağı Vocational Schools. 28 students in the experimental group were taught professional English through a programme developed according to Theme-based Teaching Model of the Content-based teaching approach. On the other hand, 28 students in the control group were taught professional English by following the current teaching programme. In the study, an achievement test consisting of two parts - content knowledge and foreign language skills (reading - writing) - was developed and implemented before and after the experiment. Furthermore, lesson plans and materials based on the principles of the theme-based teaching model of the content based teaching approach were prepared to be applied throughout the experiment. The data collected by a questionnaire were analyzed with SPSS-15 (Statistical Package for the Social Sciences). Arithmetic mean and standard deviation calculations related to the data obtained from the students' pre-test and post-test results were done and independent groups t-test analysis were applied to determine the relationship between the pre-test and post-tests results of the groups. To determine the change of the success level of the students in the control and the experimental groups and to find out whether there are significant differences between the students' pre-tests and post-tests results in the groups, the data were analyzed through independent groups t-test analysis. At the end of the study, results are generally as follows: in the pre-test, for the students in the experimental and control groups, the arithmetic mean of their points in the foreign language skills (reading-writing) and content knowledge parts of the achievement tests as well as their total grades in this test were almost the same and therefore no significant difference among their scores in the pre-test was observed. However, in the post-test, the arithmetic mean of the students' scores in the experimental group was higher than that of the students' scores in the control group and thus there was a significant difference between the groups in favor of the experimental group. At the end of the analysis of the students' achievement scores in the experimental and control groups, a significant difference in favor of the experimental group was observed in the students' writing skill scores, content knowledge scores and their total scores in the achievement test. On the other hand, no significant difference in the students' reading skill scores was observed between the control and experimental group. In short, the Vocational English Teaching Programme designed according to the theme-based teaching model of the content-based teaching approach proved effective in increasing the students' academic success in the dimensions of foreign language skills (reading-writing) and content knowledge. In the light of these findings, implications about the use of the theme-based teaching model of the content-based teaching approach with different student groups and educational levels and suggestions for future studies were mentioned. Key Words: Content-based Instruction, Theme-based Model, foreign language skills, content knowledge