Immigrant groups provided a constant alternative cultural focus to the cultures of established townspeople. Most of the demographic growth of the urban population, whether in the sixteenth century or the twentieth, was dependant on in-migration. Mortality levels were too high to permit natural replacement, let alone sustained growth. New arrivals often congregated in the same districts as others from the same region and engaged in the same occupations. This contiguity of home and employment reinforced preexisting similarities of language, culinary customs, dress, courtship, religious observance, and daily routine. If migration was intended to be temporary, there were few incentives to alter these practices. The men from the Limousin in central France who came to Paris in the early nineteenth century to work as builders continued to maintain an agrarian routine, rising at five or six in the morning and walking to their place of work. Even when they spoke French instead of their own dialect, they punctuated their words with long silences.