While accents vary by region, most Americans embrace the quirks of different-sounding brethren. But in Minnesota, the way people talk is an entire vernacular and mindset -- not just a Scandinavian vowel shift.
In essence, a group of Minnesotans chatting is the cultural equivalent of a pile of soggy blankets.
To give you insight, this 1993 video, "How To Talk Minnesotan" by Howard Mohr explains the idiosyncrasies of northern speak. The clip comes from a Twin Cities Public Television program derived from Mohr's book of the same name, and honestly, the whole thing's worth watching.
For now, this YouTube clip sets the tone, firing first with, "It's OK to feel good about things here, but there's no sense running down the street telling people about it at the top of your voice."