An investigation of utilize the grammar 아/어서and 고 in Korean language from Thai learners

Abstract

This study investigates the use of the Korean connective endings 아/어서and 고 among Thai learners, who often face difficulties due to their semantic and functional similarities. A total of 60 test items—30 requiring 아/어서 and 30 requiring 고—were designed based on Korean textbooks commonly used in Thai universities, supplemented with additional sentences unfamiliar to the learners. The participants were 275 undergraduate students from nine universities in Thailand. Both quantitative and qualitative analyses were conducted, drawing on Processability Theory (Pienemann, 1998) and Complexity Theory (Larsen-Freeman, 2012).

The quantitative results revealed an overall accuracy rate of 63.81%, with higher accuracy in sentences requiring 아/어서 (65.44%) compared to 고 (62.18%). Minor variations were observed across academic year, but the general tendency remained consistent. Qualitative findings showed that learners more accurately applied 아/어서 when the two clauses expressed a clear causal or sequential relationship, while errors frequently occurred when using 고 in contexts where verb clauses lacked explicit semantic connection.

The findings indicate that Thai learners demonstrate relatively better command of 아/어서 than 고, yet persistent errors occur in complex sentence structures and in contexts not explicitly covered in textbooks. The study highlights the pedagogical need to enhance Korean language instruction through explicit comparisons of semantically overlapping grammatical forms and the development of diverse instructional materials to improve learners’ grammatical accuracy and communicative competence.