This paper is based on the assumption that a portable tutor, as a practice-based tool, can offer students ample opportunities to improve their sentence grammar. By focusing on one specific grammar issue at a time, it presents certain sentence patterns that, through repeated practice, can eventually correct that particular grammar issue, in this case, that of determiners, bare singulars, and plurals. Significantly, this study has specific implications for Assumption University students and for Thai students in general, in that it explains why people who grow up speaking a language where nouns do not have determiners will have difficulty when learning a language that has them, for instance English. The paper begins by presenting a classification of determiners followed by a detailed description of one specific type of determiner: the bare singular count noun. The study continues with the proposed research methodology consisting of the Portable Tutor development, and the Experiment’s three main components, pre-testing, “treatment” and post-testing of the participating group of students. The paper concludes with data collection and analysis, and conclusions. <p> </p><p><strong> Article visualizations:</strong></p><p><img src="/-counters-/edu_01/0745/a.php" alt="Hit counter" /></p>