New York

For the first few minutes of our meeting, Zubin Mehta is on his cellphone with an old friend (who, it turns out, is a grandson of Muhammad Ali Jinnah, the founder of Pakistan). The friend, like Mr. Mehta, is an Indian Zoroastrian—or Parsi—and the two are making plans for dinner after the maestro and his Israel Philharmonic Orchestra finish their performance that night at Carnegie Hall. They speak in Gujarati, the adoptive language of the Parsis, who fled persecution in newly Islamized Persia in the ninth century...