Comprehension of Subtitles from Re-Translating Simultaneous Speech Translation

In simultaneous speech translation, one can vary the size of the output window, system latency and sometimes the allowed level of rewriting. The effect of these properties on readability and comprehensibility has not been tested with modern neural translation systems. In this work, we propose an evaluation method and investigate the effects on comprehension and user preferences. It is a pilot study with 14 users on 2 hours of German documentaries or speeches with online translations into Czech. We collect continuous feedback and answers on factual questions. Our results show that the subtitling layout or flicker have a little effect on comprehension, in contrast to machine translation itself and individual competence. Other results show that users with a limited knowledge of the source language have different preferences to stability and latency than the users with zero knowledge. The results are statistically insignificant, however, we show that our method works and can be reproduced in larger volume.