Background: The vocal demand on teachers may predispose them to vocal difficulties. This concern is exacerbated by unfavourable classroom acoustics and a large number of learners in a classroom in developing countries such as South Africa. There is a dearth of classroom acoustic protocols in South Africa, which intensifies the effect of noise on teachers as well as learners. Aims: The aims of this study were to determine the acoustic properties within the teaching environments and to fix the foundation-phase teachers' perceptions of their voice. Setting: The study was conducted in Foundation Phase classrooms in South Africa. Methods: A classroom acoustical screening survey was utilised to conduct classroom observations. A voice handicap questionnaire was used to determine teachers' perceptions. Results: There were two sample groups: ten schools with 31 foundation-phase classrooms and 31 teachers. Teachers perceived that their voices are affected by occupational demands, with predominantly physical symptoms being reported. Excessive background noise levels were evident in all classrooms. Air traffic noise and noise from adjoining classrooms were the main contributors. Conclusion: The need for classroom acoustic specifications and design of classrooms are essential as both teachers and learners experience the effects of noise exposure. The implementation of noise reduction in classrooms has the potential to improve the performance of teachers and learners. In a developing country, schools are unique institutions in terms of structure, and therefore additional research is required to determine what building structures may be beneficial for future school buildings. The findings could assist developing countries in the formulation of polices that align with the best practices for acoustically suitable educational settings that benefit both teachers and learners.