Amazon:

Amazon Polly is a service that turns text into lifelike speech, allowing you to create applications that talk, and build entirely new categories of speech-enabled products. Polly’s Text-to-Speech (TTS) service uses advanced deep learning technologies to synthesize natural sounding human speech.

Follow the headline link and click on the various links to get a sense of the voices. Start with Joanna (Standard). Pretty good, but there’s still a bit of uncanny valley there, perhaps in the subtle hesitations you likely wouldn’t expect in someone else’s speech.

Now listen to Joanna (Neural). To me, this sounds much more realistic and is the machine learning version of the same voice.

Good enough to fool you into thinking it’s a real person? Certainly getting closer.