This assumption that German is the largest ancestry in the U.S. shows how the ancestry chart in the article is a little misleading, because most of the 20.2 million people who claim an undifferentiated ‘American’ ancestry are thought to be of English ancestry, in addition to the 24.5 million who actually specify English ancestry. Even if we decide to exclude all the Catholic Irish, most of whom were English-speaking British subjects when they migrated, roughly half of Irish Americans, or about 15 million, are thought to be Protestants, mostly from Ulster, and therefore mostly of mainland British ancestry too. So in fact there are many more Americans of British descent than of German descent, and they still use their language. In addition, German Americans assimilated and only a small proportion of them speak German. Almost all of them speak English instead. This lack of cultural affinity in descendants has had important historical consequences. It helps to explain why German-American relations have been more distant than the ethnic chart would otherwise suggest, and why German ancestry hasn't always been a big enough factor to overcome diplomatic differences.