This month Rwanda defected, announcing that henceforward only English will be taught in the schools. It would not be overstating the case to say that this caused alarm and despondency in France. You couldn't help feeling, either, that Rwanda's trade and industry minister, Vincent Karega, was deliberately rubbing salt in the wound when he explained why French was being scrapped. "French is spoken only in France, some parts of west Africa, and parts of Canada and Switzerland," he said. (In parts of Belgium, too, actually, not to mention Haiti, but you get the point.) "English has emerged as a backbone...