In this study, the researcher had a group of unresponsive learners taking a year-long English for Specific Purposes (ESP) course in Banking and Finance Department. After the detection of the problem, "unresponsiveness," one-on-one semi-structured interviews were conducted with the learners (N=8) to find the reasons of it, and what they needed accordingly. Data analysis showed they majorly needed Turkish- (L1), which was restricted to the teaching of grammar as they found most beneficial to their learning. Thus, use of L1 for explicit grammar teaching which proceeded schema building plus implicit inferring was examined to see if and how it remedied their unresponsiveness. Systematic data collection included the learners? end-of-course written reflections (N=40) and another round of one-on-one semi-structured interviews (N=7) to further elicit their views about teaching grammar through L1. The results revealed positive evaluations regarding the benefits of L1 upon more and better input comprehension, vocabulary and grammatical knowledge development, and awareness regarding language learning. They also reported feeling less anxious and stressed, which encouraged their willingness to communicate and participate. Thus, the results verify judicious role of L1 as a scaffold to decrease affective barriers and increase comprehension in language learning.