This study aims to analyze and describe problems of short-term learning of Thai language by non-majors. Thai language education in colleges has a 50- year-long history. Many Thai language textbooks have been published and a number of curricula have been developed for those who major in Thai language in Thailand, and several pedagogies have been implemented. However, there is no research on Thai language learning by non-majors. This study analyzed errors discovered in the 10-week long Thai local specialist course offered by the Global Leadership Academy at the Hankuk University of Foreign Studies. Among the total of 142 errors, 46 of them (32.4%) were errors in vocabulary, 74 of them (49.1%) were grammatical errors, 18 of them (12.7%) were stylistic errors, and eight of them were errors in other types. Among the errors in vocabulary, the ratio of those resulting from students’ inability to understand target vocabulary and those due to the interference with their mother tongue was higher than other types. Highest among the grammatical errors were the errors related to the propositions, followed by conjunctive articles and word order. While there were also errors with adverbs, rhetoric, omissions, or negative statements, those errors were relatively smaller than the others. The results of the survey conducted with the students showed that, to enhance the efficiency of short-term language education for non-majors, it is determined the development of student-oriented textbooks and a new curriculum through the increase in the number of lecture hours by professors who are native speakers would be required. Furthermore, it is also worth considering a plan to connect the curriculum with supplementary coursework offered in Thailand. It is hoped that this study will contribute to a growing interest in the potential demand on short-term Thai language learning and stimulate follow-up research.