A couple days ago Google Assistant started sporadically announcing who some of my messages were from. I don't have headphones in. My phone is locked and in my pocket, and it will just announce who I received a message from. It doesn't do it every time, it's only once every day or two. It's a small percentage of my messages, but I don't understand why it's doing it. It also sometimes reads my calendar events aloud, but not for most of them. Again the phone is locked, no headphones. It's just announcing things to the world. Why is it doing this???