Michael has a pitch pipe. It was a gift from his brother years and years ago. Recently, Michael unburied the pipe and plays single notes for Tovina. If she is in the right mood, after hearing a note, Tovina will sing it back. Then she reaches for the pipe, puts it to her mouth, and sings the note again.
What I am trying to explain is that she thinks Michael is singing the notes and that the pitch pipe just happens to be in his mouth at the same time. She doesn't realize that he is blowing through the device. Apparently if a person wants to sing a single note for more than a couple seconds, one is suppose to put this strange object to one's mouth. I'm sure T has decided it is just one more oddity in the world those bizarre adults have created around her. Luckily for us, she's decided she's game and is willing to play along.
I'm trying to capture it on video. If I manage to get it right, I'll let you know!