"ACCULTURATION AND ASSIMILATION

In many respects, the Germans were slower to assimilate than their fellow immigrants from other countries. This was due in part to their size and in part to their overall percentage of the population. When a cross-section of basic needs can be supplied within an ethnic community, the need to assimilate in order to survive is less urgent. Germans had their own professionals, businesses, clergy, churches, and especially schools. However, second generation German immigrants were drawn more quickly into the mainstream and the survival of German communities depended upon immigration."

from http://www.everyculture.com/multi/Du-Ha/German-Americans.html

I found this on Germans. Partly because they had a very large immigration from 1840-1880 and partly because I am of German decent. Feel free to find you own examples...

Here's another http://www.theseverts.net/German.htm