Google secretly stores users’ voice searches from its voice-activated assistant Google’s Voice Search and search feature Google Now. The Guardian’s Alex Hern was the most recent one to point out this feature. Listen to your own voice recording by visiting your ” Voice & Audio Activity ” page in the Google Dashboard. There is a way to turn OFF on your Google account, but unfortunately, this will not stop Google from recording your voice. So, just avoid Google Now feature to prevent yourself.
Source: https://thehackernews.com/2015/10/ok-google-voice-record.html