In Act 1, Higgins and Eliza meet and have a volatile altercation in front of a crowd. As Eliza is crying before him, Higgins uses a simile to make her seem uneducated. The presence of the crowd around them allows Higgins to show off using figurative language and to further make fun of Eliza’s emotional breakdown. His insult is therefore partially for the benefit of those around him; he doesn’t expect Eliza to understand how she is being put down. Higgins says:
Remember that you are a human being with a soul and the divine gift of articulate speech: that your native language is the language of Shakespeare and Milton and The Bible; and don’t sit there crooning like a bilious pigeon.
Higgins’s simile compares Eliza to a pigeon that makes meaningless noise. His degradation of her allows him to seem like her superior. The purpose of this simile is to make fun of Eliza’s emotions, and highlight her inability to properly express herself. This simile also works because of its juxtaposition to Higgins’s allusions to great literature. He makes himself seem like the master of the English language, familiar with literature and culture. Higgins’ eloquent language is therefore another means of looking down on Eliza, and of showcasing his brilliance to the surrounding crowd.
In Act 2, Mrs. Pearce uses a simile to express her perception of the situation before her. Eliza has just showed up at Mr. Higgins’s house, and Higgins has considered taking her on as a pupil. Mrs. Pearce is appalled by this proposal and means to talk Higgins out of it. She believes that both Higgins and Pickering are treating Eliza’s arrival too casually. When asked what the matter is, she says:
Well, the matter is, sir, that you can’t take up a girl like that as if you were picking up a pebble on the beach.
Mrs. Pearce’s simile is intended to criticize Mr. Higgins’s behavior. She points out that Eliza has a family and a background that the men are not aware of, and her comparison of Eliza to a pebble helps underscore this point—Eliza isn't an object that can be picked up and set down at random. She accuses Mr. Higgins and Pickering of using Eliza and doing it casually, without much regard for her life or wellbeing. Her simile characterizes Eliza as someone whose life is not easily interruptible, who shouldn’t be torn from her circumstances. Mrs. Pearce's use of this simile shows the audience that she is conscious of the power dynamics at play in this scene. She understands that Eliza should have agency over her own life, and therefore recognizes how Eliza’s class and gender might put her at a powerful disadvantage against Higgins and Pickering.
In Act 2, Mr. Doolittle arrives at Mr. Higgins's house in an attempt to get money. He uses a simile as he tries to convince Mr. Higgins to keep Eliza in his care. His goal is to make it seem as though Eliza shouldn’t leave once she’s arrived, even though he is demanding compensation from Mr. Higgins. When Higgins demands that he take Eliza away, Mrs. Pearce interjects and reminds Mr. Higgins that Eliza currently has no clothing. Later in the afternoon, Eliza will be able to change into fancier garments, but at the moment she is stranded. Mr. Doolittle jumps on this line of reasoning, sensing an advantage. He says:
I can’t carry the girl through the streets like a blooming monkey, can I?
Mr. Doolittle compares Eliza to a monkey in order to reference her nudity. Like an animal, she doesn’t have the protection of clothing and therefore would be out of place if he took her out onto the street. He compares her nakedness to that of a monkey because she has already gotten rid of her "common clothes" and has nothing to take their place.
His simile also serves a more specific purpose in the conversation. Because Mr. Doolittle is hoping that Eliza will stay with Mr. Higgins and receive his tutelage—he sees it as a career opportunity for his daughter—he wants to be more convincing in his conversation with Mr. Higgins. He uses a simile in order to accentuate how stupid he and Eliza would look if she were sent away naked, impressing the impossibility of their rapid exit on Mr. Higgins.
In Act 4, Higgins uses a simile to characterize his experience at a formal event. Higgins’s poor attitude is made clear by how he talks about the event; even though it is an important benchmark in their experiment and important for Eliza, he is dismissive of their accomplishments and instead complains about his boredom. When Pickering asks Higgins whether he was at all nervous about Eliza’s success, Higgins responds with a simile that makes his experience clear:
But when I saw we were going to win hands down, I felt like a bear in a cage, hanging about doing nothing.
Higgins uses this simile to dismiss the atmosphere of the dinner, and to downplay the importance of what took place there. He compares himself to a trapped bear to give Pickering an idea of the boredom and disuse he felt. He felt that his power and strength—in this case, his intellectual ability and skill as a linguist—were insufficiently challenged. Because he saw that he was no longer necessary to Eliza’s ability to function and therefore no longer relevant, he grew very bored and frustrated. Comparing himself to a bear helps Higgins communicate both his high estimation of his worth and his sizable contributions to Eliza’s success. Instead of celebrating Eliza's growing ability to pass in society with ease, Higgins complains about having nothing to do, highlighting his ego.
In Act 4, Higgins uses a simile in a conversation with Eliza, who has expressed her anger and distress over the callous result of the experiment. Eliza feels cast aside by Higgins and Pickering; she has been continually undervalued and condescended to. After she yells at Higgins and begins to cry, she asks him what her future could even hold. Now that Higgins has deemed the experiment successful, Eliza will be released from his tutelage. Higgins tells her that she could marry, and gives her a backhanded compliment by speculating that many men might like to marry her:
It’s quite a pleasure to look at you sometimes—not now, of course, because you’re crying and looking as ugly as the very devil.
Higgins uses a simile to call Eliza ugly, contradicting his earlier insistence on her ability to marry. Comparing Eliza's tearful appearance to the devil is a way of shaming her for her emotional outburst. By implying that her expression of anger and fear has ruined her physical appearance, he makes it clear that she has not conducted herself in a ladylike manner. This slip in her composure makes her not only unappealing but also a source of evil. Like the devil, she is a malignant influence that should be avoided. Higgins's simile helps communicate the severity of his distaste for her emotion, and also implies that her composure will be an important part of her future marriage prospects.