My family forgot, over the course of 2-3 generations, how to speak German (Swiss Basel dialect and Pennsylvania Dutch), Irish, Welsh, and Scottish. My wife’s family forgot how to speak Russian, French, and German. In the place where I live (Minnesota, USA), they forgot Ojibwe, Lakota, and Menominee, along with a countless number of European, Asian, African, and South American languages. (I have a coworker who personally forgot how to speak Aymara and Quechua.)
They didn’t simply “forget,” though. They were forced to forget. US society forces families and communities to forget. From the physical punishment of African slaves and Native American boarding school students, to the shaming peer-pressure of the modern suburban Middle School, our society squeezes the languages out of communities. Our society makes plain that to be one of “us,” your speech cannot betray any trace of the “Old World.”
Forgetting about the Old World makes us Americans.