The short answer is: not all the time. But that doesn’t mean people won’t be listening to it some of the time, depending on your settings.  All three companies employ people who listen to actual voice recordings from interactions with smart assistants, but all three also offer the ability to opt out of this . In the case of both Google and Alexa, you can actually review transcripts of everything that’s been said to your smart speakers when you navigate to their respective voice assistant privacy settings.