Meet the Wongs, the "half-half" family of Gish Jen's charming new novel, The Love Wife. First there is Carnegie Wong, a second-generation American who speaks only English. Then there is his "za-va-vavoomy" wife known to everyone as Blondie. Though Blondie is pure WASP, she actually speaks passable Chinese. Their only biological child, the latecomer Bailey, is almost suspiciously blonde and blue-eyed at birth, while their two adopted daughters, Lizzy and Wendy, hail from Chinese orphanages. Something in Lizzy's features also suggests a partial Japanese ancestry, though no one can say for certain.

Next, Mama Wong. She swam through shark-infested waters to escape China to Hong Kong, then carried on across the Pacific to find prosperity in the United States. She offers her only child a million dollars not to marry the Marilyn Monroe clone. "You watch," she says of the social mobility of his prospective in-laws. "They are go down. You know why? ... They go down because they no want to go up." Later, she extends the same bribe to Blondie.

"What? You think you are white?" Mama Wong once lectured her son. "You are Wong! Wong! Wong!" Or else: "Two Wongs–two Wongs–two–don't make a white!" When the novel opens, this fearsome matriarch is losing a fight with Alzheimer's disease.

Finally, there is Lanlan. She is from a city near Shanghai, and is distantly related to Carnegie. Still, the invitation to emigrate to the United States and serve as nanny to the Wong children comes out of the blue. Before she knows it, she is cohabiting with a goat in a converted barn next to the family home in a town outside Boston. "Chinese people say Americans have no feeling," she confides in her early days. "Chinese people," she adds, "do not smell."

Aside from a few neighbours and friends, the extended Wong family holds centre stage in The Love Wife with the same mesmerizing confidence as the Lamberts of Jonathan Franzen's The Corrections. The novel, the third by the gifted Jen, is purposefully intimate in scale and event. It is also aspires to do no less than probe the cultural and linguistic dynamics of the United States that is fast emerging.

Though Lanlan, shortened to Lan, is no more aware of it than Carnegie or Blondie, she is a bomb tossed into a nascent, and fragile, domestic arrangement. In her will, the now departed Mama Wong requests her son take in their Chinese relation, knowing he cannot refuse this final filial duty. Lan's mission, coded into her very identity, is to adopt the role of the second or "love" wife in traditional Chinese households. Translated into American, she is the designated home-wrecker.

The deceased tyrant's plan is a success. "She already has the girls," Blondie complains of Lan's deepening influence over her children. "She cannot have Bailey too." Carnegie, who is struggling with his own coded impulses as a man, e-mails the relative in Hong Kong who is overseeing Mama Wong's will. "Returning Lan Now" is the title of his desperate correspondence.

The reply from China, though, is stern and fatalistic: "You have no choice but to honour her dying wishes." Buried within those wishes are a revelation about Carnegie's own past, and the true identity of Lan.

Honouring old-country secrets and abiding sweet-sour mamas are, of course, the iron rice bowl concerns of the Chinese-American novel. But Gish Jen, a genuinely funny writer, is too smart and unsentimental not to press the material in a fresh direction. Mama Wong, for instance, may be a stock character, but Lanlan is an original creation. Jen underscores the difference by inviting Lan into the inner circle of characters whose minds she inhabits in rotation. The technique, a kind of he said/she said take on the action of the plot, makes for an intimate, warm reading experience.

That plot could easily kick in 100 or so pages before it finally does. The Love Wife is delightful at the start, and stirring and sad toward the end. In the middle are passages of genial dialogue and witty observation, not always compelling or necessary.

But then the novel's real ambition, and the reason it stands a chance of quietly entering the canon of contemporary U.S. fiction, lies in its ardour for spoken language. New configurations of American families, suggests The Love Wife, are pressuring not only the nation's self-definition, but its speech. Like Maxine Hong Kingston, whose trippy, warm-hearted prose is an obvious influence, Gish Jen is all ears to both the new things members of "half-half" families say about themselves and where they live, and how they express those things.

"When I look at that boy," remarks a neighbour of the Wongs about Bailey, "all I can think is, Is this the new face of America?"