8/11/2013:
Esperanto was created in the 1870s as a universal language designed to help international communication. On this date in 1910, the Turtle Mountain Star reported a colony of Esperanto speakers had taken root in rural Stutsman County.
Frank Frankgeld had just moved his family into the area, and everyone in his home spoke Esperanto as well as they did English. Frankgeld's neighbors were mostly immigrants from Germany, Norway, and Russia, and they, too, wanted to learn Esperanto to improve communication with their neighbors. The farmers planned to set up an Esperanto school, and began to study the language on their own.
Esperanto never took hold in international trade, and it doesn't appear that Esperanto replaced English in Stutsman County for very long either.
Dakota Datebook written by Derek Dahlsad
Sources:
"Colony in Stutsman County are using universal language," Turtle Mountain Star 8/11/1910
"History of Esperanto", Wikipedia, retrieved 7/20/2013 (http://en.wikipedia.org/wiki/History_of_Esperanto)