How does the use of Text-to-Speech technology affect the effort of post-editors working into their L2?

The rise of neural machine translation (NMT) coupled with a rise in demand for localisation services has transformed the face of the language service industry (LSI) during the past few years. One of the most up-and-coming services is machine translation post-editing (MTPE), with shorter turnaround times and more affordable prices. With the rising popularity of MTPE, professionals face an increasing workload also in their first foreign working language (L2), and, as a result, they must cope with growing mental and physical fatigue. A potential solution to lower MTPE effort could be the use of text-to-speech (TTS) technology. This study revolves around an experiment investigating the MTPE effort of professionals working into their L2, from Greek into English with and without the use of TTS, as well as reporting on their perceived effort during the experiment. According to our results, the use of TTS can increase quality while post-editing, while it does not affect the temporal effort negatively in any significant way. On the other hand, it increases technical and cognitive effort as it involves more keystrokes and mouse activity. The perceived effort of the participants seems to be heavily influenced by the actual gains they had while using TTS.