Literary Devices in The Importance of Being Earnest
Oscar Wilde creates a comedic tone using puns, situational irony, dramatic irony, satire, and epigrams. Puns (a play on words so that a single word can have multiple meanings) not only reveal characters’ cleverness but also suggest Wilde’s own opinions on certain topics. Situational irony (an outcome that is different than expected) and dramatic irony (the audience knows something about a character that hasn’t been revealed) emphasize important scenes and sustain the audience’s interest. Epigrams (brief, humorous statements divulging a truth about humankind) and satire (making fun of someone or something to expose corruption), however, most distinctly reveal Wilde’s criticism of the upper classes.
Here, Wilde seems to poke fun at his own cleverness and wordplay, suggesting that some things might sound clever because they're, as Algernon says, "perfectly phrased," though in fact their cleverness is undercut by the fact that it's not logically sound. Case in point: it's no great tragedy that men don't become their mothers. Very few would want to.
Lady Bracknell puns on the word "lose," taking it to mean both that Jack has lost his parents (in the sense of them passing) and literally lost them (in the sense of their being misplaced). In this interrogation, Lady Bracknell has proven herself to be witty, bizarre, and obviously related to Algernon. Her ideas about marriage, propriety, and wealth are proper to the point of being absurd, and Wilde uses them to prove that these Grundyist ideals are entirely ridiculous.
Note that Jack's line about it being a "charming" day isn't necessarily a reference to the weather (which may well be lovely), but that it is in fact an example of a double entendre, which Jack uses to suggest he has found Gwendolen particularly charming or beautiful. Gwendolen rightly assumes that there's more to what he says, but, given that we already know it's a double entendre, she doesn't really need to say so out loud, except to show off her intelligence.
Wilde makes a pun on the word "smart," using it to mean both that Gwendolen is smart (or intelligent) and that she's dressed "smartly" (or in an elegant, impressive, sophisticated way). Thus, Gwendolen is characterized as a bright and beautiful young woman who's perhaps too smart for Jack but clearly a relative of the sharp, witty Algernon.
Algernon plays on the familiar phrase "two's company and three's a crowd," where "company" refers to the exact number of people you want in a situation, such as two lovers who think that a third person would be a third wheel or a "crowd." Algernon suggests that having a Bunbury (or, indeed, a lover) is essential in a marriage, because two people alone won't be enough for each other. Jack, of course, disagrees.
A pun on the words "Ernest" and "earnest," where one is a name and one is an adjective or character trait that Ernest Worthing displays. Of course, "Ernest" is an assumed name, and Jake isn't really earnest at all, but has been lying to Algernon since they met. The name "Ernest" then becomes the cause of many misunderstandings in the play and, thus, its primary source of humor, as the title implies.
A play on the word "understanding," which in this context refers to an engagement or agreement to marry between Lane and a woman. He didn't really want to marry this woman, which results in his believing that marriage may well be a happy situation for some people, but that it wasn't for him. Misunderstandings like this will result in most of the conflicts in the play and will be its primary source of humor.
A pun on the word "forte," as in "pianoforte," the proper name for the piano (not to be confused with "fortepiano," an earlier iteration of the piano prominent from the 18th to 19th Centuries, before the creation of the modern "grand" piano). Here, Wilde uses the word "forte" both to make a musical pun and suggest that emotional piano playing is Algernon's "forte," or strength.
Wilde puns on the word "pupil," which today usually means "student" but originally meant an orphan, ward, or minor (like Cecily) and was derived from the Latin "pupillus" or "pupa" (meaning girl). This "pupa" also refers to the larval form of a bee, which the Chasuble uses here to mean that, were he a student or "pupa," he would learn everything Miss Prism has to teach him and hand on her every word. This image, however, doesn't cover up what's obviously a sexual relationship, because it reminds the audience of "the birds and the bees."
Note the repetition in this line. It appears that three names, like three addresses, inspires confidence in someone of Lady Bracknell's social sphere and satisfied her with regards to Cecily's status and heredity. That the three names are in fact the same satirizes Lady Bracknell's old-fashioned sense of decorum while at the same time poking fun at the names of law firms and businesses, who sometimes have comical names like this one.