Imagine you’re an unknown young writer whose first collection of stories wins the Pulitzer prize. Your first novel is filmed, your second is shortlisted for the Man Booker and your next collection of stories goes straight to No.1 in the New York Times bestseller list, while prizes and honours are showered on you. Might the words ‘rest’ and ‘laurels’ come to mind? Not for Jhumpa Lahiri.

The Bengali-American author of Interpreter of Maladies and The Namesake chose instead to swap New York for Rome with her husband and two young children for what she calls ‘a trial by fire’ into a new life and a new language: for nearly three years she read and wrote exclusively in Italian. In Other Words is an account of that total immersion, published in dual-language format, the Italian translated into English by Ann Goldstein.

Some readers might see Lahiri’s experiment as a risky attempt at kicking away the ladder to her own success. Italian-savvy readers can flip between left and right hand pages and see how each language imposes its own stress and nuance. As with any translation, the reader is inevitably nagged by the question: how close is this to the original? Reading the English pages I often found myself checking Lahiri’s own words. A curious activity: attempting to touch the truth of something written in Italian by a writer whose first language is English.

The emphasis is on her linguistic odyssey, interspersed with two short fictions. Her novels and earlier stories addressed the outsider/immigrant experience with tenderness and distanced irony; her Italian writing is personal, inward-looking, exploring identity and alienation, anatomising the state of mind of a writer who has more than one ‘mother tongue’. Others have been here before her — Beckett, Nabokov, Conrad — writing in an adopted language, but life dictated their decision; Lahiri’s was a willed choice.

She occupies an enviable niche at the top of the American literary establishment, but, born in London, spoke only Bengali till the family moved to the US. ‘When I was sent to nursery school…I had to express myself in a language I barely knew.’

I can identify with that feeling of childhood estrangement: India-born, with Scottish parents; bilingual in Hindi and English, I once stood, newly arrived on a Cornish hillside, desperately shouting Hindi words. The wind whipped them away and they were lost. Lahiri retained her Bengali, though when she visits Kolkata they criticise her accent. ‘I don’t have a country, a specific culture…. I am exiled even from the definition of exile.’

This is essentially a literary memoir, a passionate love letter to language and to Italy. The facts of her life have to be gleaned between the lines; we’re not given the whole picture. How did her husband feel about the experiment? What effect did it have on the children? We do learn how it all began: on a student trip to Florence that proved a life-changer. Over the next 20 years Lahiri took Italian lessons and a PhD in Renaissance studies. The final step was the move to Italy.

Rome wasn’t all halcyon smooth sailing; there were edgy encounters in shops where her ‘foreign’ appearance was equated with a lack of Italian skill. Striving for perfection she despaired of measuring up to her own standards, but forcing herself to write only in Italian proved revelatory. This is a study of transformation — of a writer, and a woman who has forever been trying to improve herself, ‘because I’ve always felt I was a flawed person’. Recalling Ovid, and the myth of Apollo and Daphne, she longs for metamorphosis — ‘violent and regenerative, a death and a birth’. You sense the writer aching for the metamorphic moment, the breast fluttering beneath the bark, hair turning to leaves, her new language the means to regeneration. She now prefers to write in Italian: ‘A flight from the long clash in my life between English and Bengali. A rejection of both the stepmother and the mother tongue.’

For anyone remotely interested in grammar, the chapter on the minefield of Italian prepositions and the past imperfect makes entertaining reading. And there’s no academic aridity; the spare, limpid prose of Lahiri’s fiction permeates a bold and quirkily engaging self-portrait.