In his pioneering and now classic 1953 study, Nationalism and social communication, Karl Deutsch laid out a social science agenda for the study of national consciousness in contemporary and historic populations. Central to this agenda was communication, and central to communication was language: ‘If we knew how to compare and measure the ability of groups and cultures to transmit information, we might gain a better understanding of their behaviour and capacities.’ At that time historians were not paying attention to social scientists, as neither historical demography nor social science history had yet been born, and Deutsch's call remained unanswered. It took the study of the secular decline of fertility in the nineteenth and twentieth centuries to raise the question again for the European past. When Susan Cotts Watkins concluded that ‘those people who spoke a common language appeared to behave in similar ways with respect to reproduction, but they behaved quite differently from those with whom they could not communicate’, she offered one answer to Deutsch's inquiry about social communication and social behaviour. Apparently the spread of linguistic uniformity in populations living within long-established boundaries helped to disseminate information about controlling marital fertility. Throughout Europe, or more precisely Western Europe in the first half of the twentieth century, variation in fertility within nations declined and variation between nations rose.

From a different vantage point, historical questions about the process of individuation among European language communities, nationalities, and national cultures, and about communication between and within them, are inevitably questions about borders and borderlands. Nowhere is this more true than in Eastern Europe where, for the past two hundred years, few peoples remained untouched by changing borders. Official borders were alternately drawn around them and through them, separating fragments of language communities from each other, only to reunite them later and to separate them again later still. Starting in the second half of the nineteenth century, the sense of nationality, most often language-centred, became increasingly stronger, bringing with it the emergence of identifiable ‘national cultures’, entities within which, presumably, a single national language dominated and made the flow of information easier than in the past.