In at least some instances, the humor in Pygmalion is directed against the supercilious Professor Higgins and his social class that are so impressed with appearances and place so much value upon how one speaks, dresses, and acts when they are so easily deceived by Eliza as she performs correctly. Also, a couple of instances of humor illustrate that although Eliza is well-trained to appear as if from the upper class, she does not know how to think and to react as a gentlewoman, so she commits some rather humorous faux pas. So, Professor Higgins can not really “take a human being and change her into a quite different human being by creating a new speech for her.”
When, for instance, Professor Higgins visits his mother and asks permission to introduce Eliza, she makes an impression "of remarkable distinction" and when ask if it will rain, answers with pedantic correctness of pronunciation and syntax:
LIZA The shallow depression in the west of these islands is likely to move slowly in an easterly direction. There are no indications of any great change in the barometrical situation.
However, the conversation takes an ironic turn as Freddy thinks she is parodying those that consider the weather of more importance than it deserves when she replies in a similar manner a second time; he laughs, telling Liza she is "awfully funny!"
When Mrs. Eynsford Hill remarks that she does not want the weather to turn cold; she adds that there is much influenza around and spreads through families.
LIZA My aunt died of influenza: so they said.
MRS HILL [clicks her tongue sympathetically]!!!
LIZA [in the same tragic tone] But it's my belief they done the old woman in
MRS. HIGGINS [puzzled] Done her in?
LIZA Y-e-e-e-e-s, Lord love you!...They all thought she was dead; but my father he kept ladling gin down her throat til she came to so sudden that she bit the bowl off the spoon....What call would a woman with that strength in her have to die of influenza?
In addition to the humor of Liza's ingenuous failure of falling out of her pretentious role, Shaw satirizes the upper class of the Victorian Age as Freddy delights in her language, believing it the latest "small talk" and Clara Hill leaves after repeating "Such bloody nonsense!" [Bloody means By our Lady and constitutes swearing] because Liza says it and the party believes she is using the latest form of fashionable talk.