In his interview with Robert McCrum of the Guardian, DeLillo said his parents came from the Abruzzi, they wanted him to be an American, they had no desire for him to learn Italian.
In A Hermit in Paris, Calvino includes an essay on his visit to the United States. It was at the time when, he told his minders at Einaudi, people were excited by a book about a teenage boy by a writer called J D Salinger. He comments on the books available to immigrants. Some immigrants come from educated backgrounds; they end up having a bookstore to serve their needs. There are no Italian bookstores, he says: the Italian immigrants were illiterate peasants, they were excluded from literary culture in their country of origin and have no stake in participating in it in the new country.
If I remember this correctly, Jonathan Galassi, President of Farrar, Straus & Giroux, first engaged with Italian literature at Cambridge; this was a Saul-on-the-road-to-Damascus moment. (Galassi has now translated the work of both Montale and Leopardi.)
This looks like a failure of -- something. I would have said, it is not the business of, as it might be, the modestly aspiring parents of DeLillo to offer their son the sort of opportunity Galassi got as a Marshall Scholar at Cambridge. It is the business of the educational system to offer students access to the life of the mind, regardless of what their parents may be able to offer; this ought to include access to great works of literature in a language from whose cultural resources their parents had been excluded.