That same boat is carrying a lot of writers these days, most of them working in English, but others in French, German, Spanish, Japanese or even Dutch, enriching and expanding the literature of their host cultures. Some have left their native language behind after being displaced by political unrest or repression. Others have relocated and plunged into new cultures in a spirit of adventure, encouraged by the freer movement of people and ideas over the last quarter-century. A new literary diaspora has taken shape, propelled, as Isabelle de Courtivron has written in “Lives in Translation: Bilingual Writers on Identity and Creativity,” by “immigration, technology, postcolonialism and globalization,” powerful forces that have “dissolved borders and increased cross-cultural mobility.”

Image Yiyun Li, whose third novel in English, “ Kinder Than Solitude ,” was published by Random House in February. Credit... Drew Kelly for The New York Times

Ellen Litman, an émigré from Russia whose novel, “Mannequin Girl,” was published in March, said: “I’m not sure what I call myself. I’ve lived in the U.S. longer than in Russia at this point, and the longer I’m here, the further I am from that experience.”

Ms. Marciano, who grew up in Rome, acquired English more or less as her heroine Emma did, as a teenager. She lived in New York in her 20s and, while spending 10 years in Kenya, wrote her first novel, “Rules of the Wild,” in English after a failed start in Italian. Today she lives in Rome, but English has become her second skin.

“You discover not just words but new things about yourself when you learn a language,” Ms. Marciano said. “I am a different person because I fell in love with English. I cannot revert. I cannot undo this. I am stuck.”

Two waves of emigration from the former Soviet Union, the first in the late 1970s, the second after the nation’s collapse, have yielded a bumper crop of Russian writers who have made English their own. Some, like Gary Shteyngart, and Boris Fishman, whose first novel, “A Replacement Life,” is being published by Harper in June, came to the United States as children and absorbed English by osmosis. Others, like Ms. Litman, Lara Vapnyar, Kseniya Melnik, Olga Grushin and Anya Ulinich, left the Soviet Union in their teens or early 20s, late enough in life to make the transition to another language a conscious effort.