> I would assume that the OS X TTS engine is the same as Siri's as it would be available in High Sierra.
Nope, macOS uses a different set of voices for TTS, which are named differently as well. They work offline and are nowhere as good as Siri.
Nope, macOS uses a different set of voices for TTS, which are named differently as well. They work offline and are nowhere as good as Siri.