The Greek word "Chrysostomos" in the tenth paragraph of Telemachus compounds Chrysos (gold) and stoma (mouth). Several orators of antiquity acquired this epithet "golden-mouthed," notably St. John Chrysostomos (ca. 349-407), a renowned speaker and one of the Three Holy Hierarchs of the Greek Orthodox faith. The odd one-word sentence appears to comment on Mulligan's "even white teeth glistening here and there with gold points," in the previous sentence. It is the first appearance in Ulysses of the book's revolutionary stylistic device of interior monologue, often mislabeled stream of consciousness.
Bernard Benstock says of this cryptic one-word sentence, "As a comment on Buck's dental work it is redundant; as a narrative comment it is out of place" (Critical Essays, 3). Who is thinking this odd thought? There is only one good possibility: the person standing next to Buck Mulligan, watching his moving mouth, listening to his verbal pyrotechnics. Stephen is the kind of person who can muse on church fathers before his first cup of tea, and also the kind of person who would notice that one of Mulligan's middle names is "St John," linking him with St. John Chrysostomos. And, as Benstock also observes, Stephen repeatedly thinks of Mulligan in damning one-word judgments: "Usurper" at the end of Telemachus, "Catamite" in Scylla and Charybdis, "Chrysostomos" (i.e., glib speaker) here.
Joyce said often that the minor French novelist Édouard Dujardin inspired him to create the internal, unspoken thoughts of his characters in this way. Ellmann tells the story of how Joyce came upon the novel Les lauriers sont coupés (1888), and he describes the technique of Dujardin’s experimental novel, an extended soliloquy that does without any third-person narration (126). He also quotes several sayings that evoke the book’s appeal to Joyce. One is a sentence of Fichte that inspired Dujardin: “The I poses itself and opposes itself to the not-I.” The others are Dujardin’s: “the life of the mind is a continual mixing of lyricism and prose,” and the novel must therefore balance “poetic exaltation and the ordinariness of any old day.”
In “Chrysostomos,” one can hear Joyce's deployment of these Symbolist oppositions of a poetic inward reality and a mundane outward environment. The word takes us for one moment into the fanciful realm of Stephen’s thoughts, where ordinary images like gold and white teeth become imbued with psychological, moral, and spiritual signifiance. Stephen's single word defines the "not-I," Mulligan, as a glib coiner of elegant phrases who does not use language in the service of truth. This is our first real glimpse of the "I" that is Stephen, an ego desperately defining itself in opposition to other human beings.
The term that Joyce used to describe Dujardin’s innovation, monologue intérieur, did not originate with either man. According to Ellmann, Valery Larbaud found the expression in Paul Bourget’s Cosmopolis (1893) and gave it to his friend Joyce as a tool for discussing the author’s big new book (519). Joyce soon felt that the phrase had outlived its usefulness and went searching for others that might point readers toward what he was trying to do in the novel. But his endorsement of “interior monologue” should recommend it over the similar phrase, “stream of consciousness,” that readers often apply to Ulysses. Only Molly Bloom’s interior thoughts can justly be called streaming.
 Kevin Birmingham makes this point well in The Most Dangerous Book: The Battle for James Joyce's Ulysses (2014). He says of the novel's style, “Thoughts don’t flow like the luxuriant sentences of Henry James. Consciousness is not a stream. It is a brief assembly of fragments on the margins of the deep, a rusty boot briefly washed ashore before the tide reclaims it.”