The National Jukebox
According to Prof. James Leary of the University of Wisconsin-Madison, dialect recordings associated with German Americans (or the "Dutch" as the English of the 18th and 19th centuries referred to anyone from a wide range of Germanic regions) entertained and appealed to both German-American audiences and mainstream Americans.
Take some time to listen to comic songs, skits, and recitations such as "The Germans' Arrival," "Hans Krausmeyer and His Dog Schneider," "Krausmeyer's Wedding Party," "Louisa Schmidt," "Fritz and Louisa," "The Happy German Twins," and "It Takes the Irish to Beat the Dutch." Some of these recordings may also be found and listened to by searching for "German dialect" or "Dutch dialect" on the Cylinder Project site at University of California-Santa Barbara
You may also wish to read Prof. Leary's paper, "Dialect Songs among the Dutch" [PDF] and listen to audio samples associated with the work
And to examine German-American ethnic stereotypes through cartoon images found on popular postcards in the 20th century, see: