It's difficult to read "In Other Words," Jhumpa Lahiri's book about her love of Italian, without thinking of V.S. Naipaul's famous quote about his identity. In 1954, he wrote, "In England I am not English, in India I am not Indian. I am chained to the 1,000 square miles that is Trinidad; but I will evade that fate yet."

The comparison is apt not because Naipaul and Lahiri share Indian heritage but because, as Lahiri writes, "I've always lived on the margins of countries, of cultures." When she lived in the United States, strangers treated her as foreign. On visits to India, some considered her too Western. It is this tension, between the need to belong and the need to grow, that is the basis for her beautiful new work of nonfiction.

Few people carry an obsession as far as Lahiri has taken her passion for Italian. Her love affair began in 1994, when she bought a pocket dictionary before a trip to Florence. She wrote her doctoral thesis on Italian architecture's influence on 17th-century English playwrights. But despite taking Italian lessons in the 2000s, she felt as if she were hugging the shore, "swimming along the edge of that lake." In 2012, she takes the plunge: She and her family move to Rome.

Lahiri wrote "In Other Words" in Italian. Her original text and Ann Goldstein's English translation are on facing pages, a practice common to works of poetry in translation. Its use here reinforces that this is as much a work of poetry as prose. The book contains two short stories, but most of the chapters chronicle her attempts to master her new language and adjust to life in Italy.

Many sentences begin with "I think," a weak construction that implies a lack of confidence. But it underscores her feelings of disenchantment, of "trying to get away from something, to free myself." And she is candid about her career and the perils of early success. (Her debut short story collection won the Pulitzer Prize in 2000.) "I received a prize that I was sure I did not deserve. … By writing in Italian, I think I am escaping both my failures with regard to English and my success."

The Lahiri in these pages is at a crossroads. She likens herself not just to Beckett and Nabokov, earlier authors who wrote in adopted languages, but to Henri Matisse, who late in life switched from painting to a hybrid of mosaic and collage. He, too, "felt the need to change course, to express himself differently."

"In Other Words" is the portrait of a writer who spent her first decades chained to the thousands of square miles that is the life of an author of English and now yearns to break free.

Michael Magras is a member of the National Book Critics Circle. His work has appeared in the Chicago Tribune, San Francisco Chronicle, Houston Chronicle and BookPage.