Effects of theme-based grammar instruction on the enhancement of english writing ability of thai EFL students

Writing is one of the important language skills for effective communication. In the classroom, students need to write several types of writing assignments both in their language class and other subject-matter classes. Meanwhile, in the workplace, employees need to develop their writing ability since it directly influences hiring decisions. Concerning the importance of writing ability, the present study chose theme-based instruction, teaching a language through content matters, as a treatment for teaching English grammar and structures, namely theme-based grammar instruction. It explored the effects of theme-based grammar instruction on the enhancement of English writing ability of Thai EFL students. To answer such an issue, twenty-seven Thai EFL undergraduate students at a public university in Nakhon Pathom Province, Thailand were recruited. The data were collected from the pre-test, post-test, and interview responses. The results showed that after the treatment, the students had improvement in their English writing ability with statistical significance (t = 3.091, p =.005). From the pre-test to post-test, grammatical errors were reduced from 122 errors to 56 errors while lexical and other writing errors decreased from 93 errors to 52 errors. The interview of the students also indicated that they had positive attitudes toward theme-based grammar instruction that helped improve their English grammatical knowledge and writing ability.