do you see her practising her singing?

It re-runs all the time..I am watching it right now.

Well, I saw one where she was walking through a hotel lobby and this poor guy whose job was to play the piano in the lobby was doing his thing. I call him a "poor guy" because Whitney walks up while he's playing and decides to sing. He doesn't seem to have any idea who she is, she's telling him to change the key and the tempo and stuff and he just keeps trying to churn out background music in this hotel. Finally she stomps off and he just keeps playing.

Then there was the time she goes to Herrod's with Bobby and he makes her mad in some way and she goes "Bob-BAY! I'm not doin' this with you....TOOOODAAAAAAAAAAY!" (Last word sung.)

But generally, no, you don't hear her sing more than a phrase or two.