Two or three lines: a mixed-methods study on subtitle processing and preferences

The typically recommended maximum number of lines in a subtitle is two. Yet, three-line subtitles are often used in intralingual Englishto- English subtitling on television programmes with high information density and fast speech rates. To the best of our knowledge, no prior empirical work has contrasted the processing of three-line with two-line subtitles. In this study, we showed participants one video with two-line subtitles and one with threeline subtitles. We measured the impact of the number of lines on subtitle processing using eye tracking as well as comprehension, cognitive load, enjoyment and preferences. We conducted two experiments with different types of viewers: hearing native speakers of English, Polish and Spanish as well as British hard of hearing and deaf viewers. Three-line subtitles induced higher cognitive load than two-line subtitles. The number of lines did not affect comprehension. Viewers generally preferred two-line over three-line subtitles. The results provide empirical evidence on the processing of two- and three-line subtitles and can be used to inform current subtitling practices.