When you move to another country as an adult, the language flows around you like a river. Perhaps a child can immediately abandon himself to the current, but most older people will begin by picking out the words and phrases that seem to matter most, which is what I did after my family moved to Cairo, in October of 2011. It was the first fall after the Arab Spring; Hosni Mubarak, the former President, had been forced to resign the previous February. Every weekday, my wife, Leslie, and I met with a tutor for two hours at a language school called Kalimat, where we studied Egyptian Arabic. At the end of each session, we made a vocabulary list. In early December, following the first round of the nation's parliamentary elections, which had been dominated by the Muslim Brotherhood, my language notebook read: On many days, I went to Tahrir Square, to report on the ongoing revolution. If I heard unfamiliar words or phrases, I brought them back to class. The following month, I learned "tear gas," "slaughter," and "Can you speak more slowly?" "Conspiracy theory" appeared in my notebook on the same day as "fried potatoes." Sometimes I wondered about the strangeness of Tahrir-speak, and what my Arabic would have been like if I had arrived ten years earlier. But it would have been different at any time, in any place: you can never step into the same language twice. Even eternal phrases took on a new texture in the light of the revolution. After I could understand some of the radio talk shows that cabbies played, I realized that callers and hosts exchanged Islamic greetings for a full half minute before settling down to heated arguments about the new regime. Our textbook was entitled "Dardasha"--"Chatter"--and it outlined set conversations that I soon carried out with neighbors, using phrases that would never be touched by Tahrir: "May peace, mercy, and the blessings of God be upon you." One of our teachers, Rifaat Amin, prepared a five-page handout entitled "Arabic Expressions of Social Etiquette." This supplemented "Dardasha," which also featured some lessons about social traditions, including the evil eye, the belief that envy can cause misfortune. In "Dardasha," icons of little bombs with burning fuses had been printed next to the kind of phrase that, even during a revolution, qualified as explosive: "Your son is really smart, Madame Fathiya."