The revival of Hebrew as a living language has often been called a modern miracle, a series of events without natural causes. A tiny group of idealists decided about the turn of the century, in a small area now known as Israel, to insist upon the use of Hebrew. In this they were guided by the scholarly example of Eliezer Ben Yehuda who, about 1882, introduced spoken Hebrew into his home and circle of friends. The beginning of modern Hebrew, a fairly clumsy medium at first, was a stubborn act of will without benefit of habit, convenience, or even clergy (religious circles objected to the secularization of the Holy Tongue). By the end of the First World War Hebrew had gained the adherence of the younger generation, and further growth could depend increasingly on the kind of regularities of language acculturation that this paper will be concerned with. Yiddish and German continued to dispute the hegemony of Hebrew with ideological and practical claims of their own, but once Hebrew had become the language of instruction at all levels of schooling in 1913 the outcome was hardly in doubt. The question ceased to be one of what language would be adopted by the Jewish population but became one of how quickly the shift to Hebrew would take place. Equipped with the results of foresighted population surveys, Bachi (1956) skilfully analyzed the growth of Hebrew language use and of the variables that could be correlated with differential rates of growth. The present paper is a brief and modest attempt to update Bachi's admi? rable study by including 1961 census data (which, by the way, were obtained under the directorship of Professor Bachi in his capacity as Government Statistician). We shall place special emphasis on the fate of mother tongues introduced into the country by Jewish immigrants. A small sample of Israelis originating in Rumania will illustrate aspects of shift and maintenance in greater detail. Pre-contact experiences and context of settlement may serve to explain the grosser aspects of language shift and maintenance (after a