Throughout the novel, Wharton uses various dialects to help depict the differing social classes and personal backgrounds of various characters. The first instance of this is in the case of Mrs. Heeny, the Spraggs' masseuse and a sort of surrogate mother to Undine. Mrs. Heeny loves to keep up with the happenings of high society, as she says to the family in Chapter 1:
"I should say I did. I manicured him for his first society portrait—a full-length of Mrs. Harmon B. Driscoll." Mrs. Heeny smiled indulgently on her hearers. "I know everybody. If they don't know me they ain't in it, and Claud Walsingham Popple's in it. But he ain't nearly as in it," she continued judicially, "as Ralph Marvell—the little fellow, as you call him."
Heeny speaks differently from the Spraggs and from all the high-society characters in the book. She uses "ain't" liberally and is fond of blunt declarations, as opposed to the cautious delicacy and ironic humor of Mr. and Mrs. Spragg. Heeny's speech also notably contrasts the narrator, which strikes a stuffy, verbose tone.
Heeny is not, as might be assumed, looked down upon for her more formal way of speaking. Instead, her distinct dialect helps characterize her as a watchful outsider of the Fifth Avenue social scene, and thus a valuable and shrewd judge of its people. Mrs. Spragg, just before the passage above, respecting Heeny's judgement, eagerly asks her whether she's met Popple. And Undine, trusting Heeny implicitly, reacts immediately to her comment about Marvell. Even the narrator, though with some irony, remarks that Heeny speaks "judiciously." Wharton, throughout the novel, aims to show that high social class does not necessarily confer good character or a good conscience. An early example of this is the Spraggs' trust in Heeny despite her lower class, which is shown primarily through her dialect.
Peter van Degen, a talkative womanizer, sits down next to Undine at the opera in Chapter 5. Peter has a very distinctive way of speaking that identifies his character as a rebellious member of the upper crust. He speaks in a multitude of short phrases without rest, talking at Undine :
Queer go—I happened to see your friend there waving to old Popp across the house. So I bolted over and collared him: told him he'd got to introduce me before he was a minute older. I tried to find out who you were the other day at the Motor Show—no, where was it? Oh, those pictures at Goldmark's. What d'you think of them, by the way? You ought to be painted yourself—no, I mean it, you know––you ought to get old Popp to do you. He'd do your hair rippingly.
Peter has a transatlantic dialect, filled with elegant vocabulary and showing his education, but he also speaks with nicknames, banters indelicately, and uses slang. This dialect typifies Peter's character, presenting all the superiority of the upper class while being rebellious and irreverent. Undine notes, in fact, that "Mr. Popple's talk was certainly more brilliant and purposeful." Undine's comparison is perhaps the best description of Peter's dialect. He sounds similar to Mr. Popple, as they both speak the language of Fifth Avenue society. But Peter does it with none of the brilliance or purpose of the others: he bounces thoughtlessly from topic to topic and talks with no decorum or politeness. This dialect continues throughout the novel, and exemplifies Peter's nature as a fickle flirt who never has to worry about money; his thoughtless and vapid disposition is depicted in the way he speaks.