I thought I'd just add another fun fact/data point here. This is obviously my personal opinion. I have to use TTS to use my computer with a screen reader, and for that, I mostly prefer more synthetic speech. When I read long form text like books, articles, etc. I do prefer more natural voices, but for doing actual work like reading code or simply using user interfaces, I like the predictability of more synthetic/algorithmic speech. Apple added the neural Siri voices to the new VoiceOver. They sound incredible but the quality of the voice also brings latency with it. Something like ESpeak is much, much more performant and predictable, and it speeds up much better. I use my TTS at a very fast rate and I find that the more natural a voice, the harder it is to understand at that speech rate. Neural voices speak the same phrase of text differently every time it's uttered. Slightly different intonation, slightly different speech rhythm. This makes it hard to listen out for patterns. So for me there's definitely still a place for synthetic speech.