If you search for the "So what is the campaign about?" example, then compare ground truth vs synthesis, it's clear that it still appears to filter out accents.

If you search for the "So what is the campaign about?" example, then compare ground truth vs synthesis, it's clear that it still appears to filter out accents. To give another data-point: a few examples later a man with British accent suddenly sounds American. Then again it intuitively makes sense to me that any speech synthesis will "regress to the mean" of the training data, unless it's explicitly trained to distinguish dialects. The "Speaker’s Emotion Maintenance" examples later on give the impression that that should be possible though. Either way it's still an impressive achievement to my layman's ears!