In the past two decades bilingual education has become an educational movement and a field of academic inquiry of remarkable growth throughout the world. At first glance this appears to be the outcome of the increasingly hegemonic role of a few languages like English in the western world and countries economically affiliated to it, Russian in the multilingual republics of the Soviet Union, and Putonghua in the People's Republic of China. But a closer look at the first of these areas—the one better known to us—shows how complex the dynamics of language spread and language change are in diverse sociopolitical contexts.