The novel is written in a stream of consciousness narrative structure and follows the character of Linda Hammerick as she comes of age.

Her present mingles with her past as she learns of her heritage and deals with death, sexual abuse, cancer, adoption, unwanted pregnancies, and family issues.

Throughout all of these experiences, Linda lives with a secret extra sense, the ability to taste words, which she later discovers is a form of synesthesia.

She is a New York lawyer who grew up in Boiling Springs, North Carolina, and she has a form of synesthesia that causes her to taste words when she hears them.

In part two of the book, “Revelation,” we learn more about her long-term relationship with Leo, which is only briefly mentioned in the first half of the novel.

Linda’s Vietnamese roots are not revealed until the very last scene of “Confession,” when she is graduating from Yale and they call out her birth name: Linh-Dao Nguyen.

At this point, several pieces of the puzzle that is Linda’s life fall into place for the reader, and throughout the second half of the novel she directly addresses the problems she faced as a Southerner who looked different than people thought she should.

When Kelly is a teenager, she becomes pregnant and leaves town, only revealing the father of the child—the pair's shared childhood crush, Wade—when Linda returns to Boiling Springs as an adult.

Harper is closeted for most of the novel, but reveals to his family that he is gay when he begins seeing Boiling Springs's funeral director, Cecil.

When he and Cecil die suddenly in a plane crash, Linda returns to Boiling Springs and is able to come to terms with his death.

Thomas is Linda's adopted father who corresponds with her Vietnamese mother Mai-Dao after she leaves him to go back to her fiancé in Vietnam.

Other characters in the novel include Linda's neighbor and childhood-crush Wade and longtime boyfriend Leopold "Leo" Thomas Benton.

The novel opens with an epigraph from To Kill a Mockingbird, immediately followed by the title of the first half of the novel—“Confession”—which focuses most heavily on Linda’s childhood.

Kelly’s encounters with Bobby are known fairly early, but Linda reveals the details of her rape slowly as the novel progresses.

At this point, Baby Harper has come out to his family as gay—something that Linda suspected for a long time, but he never said to anyone outright—and is with a man named Cecil, who has a funeral home.

When Linda finally works up the nerve to tell Leo, instead of simply comforting her and going back to Boiling Springs as she asked him to, he proposes.

Justin Mellette states that Bitter in the Mouth is an essential Southern novel in which a multiplicity of voices joins beyond the black/white racial binary to encourage readers to consider the "Global South".

Jennifer Ho looks closely at Linda's perceived race in a chapter in her Racial Ambiguity in Asian American Culture.

[6] In a review in the journal Gastronomica, Margot Kaminski describes how the novel uses Linda's synesthesia as a way to make her more unique.

Initially, Linda mentions early in the book that her family, the Hammericks, rose to their status of wealth through the cotton industry which she then clarified that means they owned slaves.

This narrative style forces readers to look deeper past what is written and avoid making assumptions at face value.

Linda's synesthesia is a clever tool used by Truong to describe the experiences of embodiment and trauma that many immigrants feel when they are racialized in America, specifically the South.

Borders are being crossed violently in Linda's own personal space, which reflects the broader global issues that she experiences, but are bigger than herself, such as the Vietnam War and the life of an immigrant in the American South.

In his review in The New York Times, Roy Hoffman called the book "a moving investigation of invented families and small-town subterfuge, a search for self heightened by the legacy of Vietnam and the flavors of language.

"[10] In the Los Angeles Times, Diane Leach wrote, "Truong's bone is the outsider's plight, and her pen is a scalpel, laying perfect words down along that nerve until even the happiest reader understands what it means to forever stand apart from your family and the larger society you inhabit.

"[11] Writing in The Boston Globe, Diane Wright called the novel "a beautifully written, complex story of self-discovery.

The novel is prefaced by a quotation from To Kill a Mockingbird by Harper Lee; Linda later discusses how she relates to the character of Scout.

The history of Virginia Dare and the Wright Brothers' first flight plays a prominent role in her thoughts throughout the novel.

Another historical figure that Linda relates to is George Moses Horton; his poetry and life are mentioned several times in the novel.

By adding her narrative into these Southern references, Truong stresses the importance to re-examine the "body" represented in South literature.