[kyrra]

GOOG-411 likely gave Google a large datasource for voice training.

https://en.wikipedia.org/wiki/GOOG-411

[virtuallynathan]

Yep: https://static.googleusercontent.com/media/research.google.c...

And also all of the time people talk to Google Home, Assistant, etc. Google Voice voicemails, and perhaps calls? Also, all of the audio and any recorded calls posted to YouTube.

[hprotagonist]

I believe this has been explicitly confirmed, but I can't find a source at the moment.

[nappy-doo]

As a Xoogler, that is my understanding. Similarly, all the Google Assistants and (now) Google Homes out there are also being used.

[chaoticmass]

Ah, I remember using this service a lot in the pre-smart phone days.

[joshred]

Also Google voice, voicemails.