The study of The Investigation of Grammatical Instruction on Pragmatics of Thai EFL Learners: A Case of the 1st Year-English-Major Students of Nakhon Phanom University, Thailand aims to investigate whether the grammatical instruction affects pragmatic acquisition of Thai EFL learners' scores, and to examine what types of the request speech act influence pragmatic acquisition of Thai EFL learners are. The samples are 31 students, categorized by the purposive sampling studying in the English Major at the Faculty of Liberal Arts and Science, Nakhon Phanom University. The instruments are pretest and posttest of Discourse Completion Test (DCT), grammatical tasks, exercises, role-plays, and interviews. Statistics used in the research conduct is the t-test. The results reveals that the posttest scores (Mean = 6.39, SD = 2.33) were significantly higher than the pretest scores (Mean = 3.16, SD= 1.85), indicated by t (30) = 8.05, p < .05, d = 1.53. The grammatical instruction used in pragmatics was effective, and the students could effectively improve their pragmatic acquisition ability. There are 12 types of speech acts frequently used by learners. The highest-top three frequency used by Thai EFL learners are Attention-getter accounting for 30.28 %, Softners accounting for 20.80 %, and Emphasis of Importance accounting for 15.90%. The last-top three frequency used by Thai EFL learners are Intensifier accounting for 0.91%, Hesitators accounting for 0.31%, and Disarmers accounting for 0.31%. Pragmatic acquisition of speech act should be taught through the topic of English courses and in the curriculum for longitudinal study.
Arnunnit Manorom, Nakhon Phanom University, Thailand