Pan Z.Mahidol University2025-07-042025-07-042025-06-01Languages Vol.10 No.6 (2025)https://repository.li.mahidol.ac.th/handle/123456789/111092This research investigated the use of I think as different types of markers by Thai learners of English as a foreign language (EFL) to determine whether the use of I think by Thai intermediate- and advanced-level EFL participants showed any significant differences. The types of markers and the functions of I think used by the Thai EFL participants were identified, as were their inappropriate uses of I think. In total, 72 Thai EFL participants were involved in this research, and dyadic English conversations were conducted for data collection. The statistical results illustrated that the Thai intermediate-level EFL participants used I think significantly more often than the Thai advanced-level EFL participants, particularly as a stance marker (SM). By contrast, the Thai advanced-level EFL participants used I think significantly more often as a pragmatic marker (PM) and as a politeness marker (PoM) than the Thai intermediate-level EFL participants. The Thai intermediate-level EFL participants mainly used the SM I think to express a subjective evaluative stance, while the Thai advanced-level EFL participants used I think across a broader range of markers and functions. Their inappropriate uses of I think are also discussed.Social SciencesArts and HumanitiesArticleSCOPUS10.3390/languages100601452-s2.0-1050092925672226471X