The low enrolment, lack of interest, exacerbated by the general poor performance in physical science in South Africa paints a gloomy picture about the status of physical science in the country. Despite the fact that there might be other factors at play, one factor which cannot be ignored is the discourse about the use of language in the science classroom as viewed by physical science teachers. In the study reported on here a quantitative methodology was followed in which a closed-ended questionnaire survey was used as data collection tool. In the study we examined South African physical science teachers’ perceptions about the language use in science classrooms, and the study was informed by the Vygotskian socio-cultural theory (SCT). The target population from which a sample size of 37 physical science teachers was systematically sampled was high school classroom teachers and learners in Grades 10, 11 and 12 in the Ngaka Modiri Molema district of the North West province of South Africa. The study revealed that physical science teachers encountered difficulties with meanings of non-technical words used in science context. The conclusion drawn was that many physical science teachers were not proficient in the discourse of the science classroom and this often compromised their effectiveness in the teaching and learning of science. The main difficulty was confusion in differentiating between technical and non-technical words and the lack of convincing explanations of meanings of these words in teaching and learning. Key among the recommendations of this study was the need to address teachers’ challenges with regard to the language use and the implications thereof.