In 1835-1836, young Harriet Robinson, the "servant" of Lawrence Taliaferro and Elizabeth Dillon Taliaferro, "wintered over" with them at the St. Peter's Indian Agency compound (Lawrence Taliaferro was Indian Agent to the Sioux) one-quarter mile outside the walls of Fort Snelling, in what is now Minnesota.
The Taliaferros were not without their own linguistic shortcomings - they pronounced their family name "Tolliver". However, in her new book Mrs. Dred Scott: A Life on Slavery's Frontier Lea VanderVelde reveals that an Englishman who wintered over at Fort Snelling with them was pronunciationally challenged to the point of being disfunctional (emphasis added):
One last summer visitor to pass through the Agency was an English geologist who was leading a small American-sponsored expedition in search of mineral deposits. George Featherstonhaugh (pronounced "fanshaw") made a trip up the St. Peter's River, which the Sioux called the "Minnaysoter". Like the artist [George] Catlin [who had visited the Agency and Fort that summer], this geologist was a man of grand ambition. Featherstonhaugh advocated a revolutionary notion for the times: that geology was the science of nature, not of any particular country. He was convinced that American rock formations correlated to those in England. The idea that geology was history rather than national geography was revolutionary.