Complex sentence: It has been posited that the Pennsylvania Dutch could be the source of the term, which would translate roughly as Schwarze Deutsche in German, but the term has never been encountered in any written record among the Pennsylvania Dutch.
Split into simpler sentences: It has been posited that the Pennsylvania Dutch could be the source of the term, which would translate roughly as Schwarze Deutsche in German. Unfortunately, the term has never been encountered in any written record among the Pennsylvania Dutch.