Poor performance in subjects like mathematics and physical science in basic education is the theme of much debate. This inquiry examined the use of mother-tongue (in this case Sesotho) subtitling of English language videos on selected themes in the Grade 12 physical science curriculum as a possible vehicle to increase learning. An empirical exploration was conducted to define if and how mother-tongue subtitling (of English language videos) influenced the comprehension of Grade 12 learners from two former Department of Education and Training (DET) schools. Grade 12 physical science content material was divided into six videos and displayed to two groups of participants. One of the two groups (control group) watched the material without subtitles while the second group (experimental group) watched the same material subtitled in Sesotho over a six-week period. The results of the comprehension test that was written after this period points out statistically significant improvement in the marks of the experimental group.