In most universities in South Africa, English is still preferred as the medium of instruction. However, most schools in South Africa have adopted a home-language education approach. Those school students then have a lower English proficiency compared to other students from English schools. Providing these students with instructional assistance with subtitles is essential to their learning. In recent years, advances in automatic speech recognition systems made it possible to automatically generate subtitles. This automation does, however, come with its own issues, namely: speech inaccuracy, timing issues of subtitles, etc. This study will investigate the effect of automatically generated subtitles on comprehension and cognitive load. Findings indicated that the subtitle types differed in the presentation speed of consecutive subtitles. This significantly influenced the comprehension of the participants that had automatic subtitles by 10%. Professionally creating subtitles is expensive and time-consuming, but also has more advantages and positive effects than automatic subtitles.