How we cite our quotes:
HIGGINS [to Pickering as they go out together] Let's take her to the Shakespear exhibition at Earls Court.
PICKERING. Yes: let's. Her remarks will be delicious.
HIGGINS. She'll mimic all the people for us when we get home. (3.262-264)
Often, Higgins and Pickering do not seem to treat her like a human being. Her remarkable abilities are simply a source of entertainment for them.
PICKERING [stretching himself] Well, I feel a bit tired. It's been a long day. The garden party, a dinner party, and the opera! Rather too much of a good thing. But you've won your bet, Higgins. Eliza did the trick, and something to spare, eh? (5.8)
Trick, indeed. Higgins and Pickering talk about Eliza as if she were a pet, a performing animal.
LIZA. Oh! if I only COULD go back to my flower basket! I should be independent of both you and father and all the world! Why did you take my independence from me? Why did I give it up? I'm a slave now, for all my fine clothes. (5.231)
Eliza is not, of course, literally enslaved. And Higgins has no intention of chaining her up. Her training, however, makes her unable to go back to her old ways. She is no longer being manipulated actively; rather, the effects of the manipulation are unshakeable.