When Fargo was released in 1996, “Minnesota speech” was largely unknown to the majority of the American populace. With a handful of exceptions, the dialect had little representation in popular culture. The film’s appeal lies not only in the quality of its direction and acting, but also in its exposure of a novel culture and regional voice dwelling in our country’s north:
As such, the dialect is unique among staples of regional humor. When an Englishman jokes about a Scouse accent, it’s likely he has heard actual Liverpool natives speak. Americans imitating New Yorkers probably have exemplars like Jimmy Cagney or Robert DeNiro in mind. Minnesota accent humor, by contrast, feels second-hand. Few cast members of the film were Minnesotan, and the actors’ larger-than-life accents gave birth to wilder exaggerations (e.g. 1999’s Drop Dead Gorgeous).
Which brings me to the FX Network’s TV series Fargo, which relates to the world of the film without quite being a sequel. Like the movie, the series centers around a mild-mannered Minnesotan who becomes an unlikely criminal (Martin Freeman‘s Lester Nygaard to William H. Macy‘s Jerry Lundergaard) and a police officer who hides a sharp mind under layers of polite Scandinavian reserve (Allison Tolman‘s Molly Solverson to Frances McDormand‘s Marge Gunderson). As you can tell from rhyming last names, the parallels are not quite accidental.
In both the film and series, local characters’ speech contrasts with that of criminal outsiders with out-of-place speech patterns (Billy Bob Thornton and Adam Goldberg to the film’s Steve Buscemi and Peter Stormare). The juxtaposition is underscored when Thornton tricks gullible police interrogators by donning a flawless “stage Minnesotan” accent, a wry comment on the two decades of mock North-Midwesternese we’ve been exposed to.
That being said, I find that “the accent” doesn’t factor into the show as heavily as it did in the film. The voice and speech work is subtle enough, in fact, that when an actor does go “full Minnesota” in the series it seems out of place. Tolman and Freeman are particularly restrained with all the monophthongal o’s and North Germanic inflections, keeping the accent more of an undercurrent than a deluge (although McDormand and Macy were likewise subtle compared to later attempts).
But I’m not sure the film’s top-billed players solidified the accent’s mythology in the first place. What really fixed the accent in the minds of those who saw the film, I think, were all those detailed bit parts inhabiting strange worlds unto themselves (who can forget Steve Park as Mike Yanagita?) On the show, smaller roles seem mostly filled out by day players, with something akin to marked Canadian Prairie English as a substitute lect.
And that underscores a larger difference between the two media: the limitations of North American television itself may factor into the accent’s lack of prominence. I recall Jon Hamm once saying something to the effect that TV is like a moving train that you can either move with or get run over by. It’s an environment, in other words, of single-takes and non-existent rehearsal (Martin Freeman has actually said something about this specific show to that effect).
As such, I’m not sure it’s the greatest environment for ace dialect simulation. That may be why many of the great regionally-focused American shows of the recent “Golden Age” of TV either didn’t get overly fussy with accents–as in the case of the The Wire and Mad Men–or cast actors with an intimate understanding of the dialect in question–e.g. The Sopranos.
That’s not to say there isn’t good work of this kind on TV; Orphan Black and The Americans have really well-honed accents that serve an important dramatic purpose. But I suspect it’s harder to get an entire cast on the same page with a regional twang than is possible with a film or play.
 The first two syllables of “Solverson” aren’t the most subtle, either.
 I could never tell if Stormare’s casting was intended to tip a hat to Minnesota’s Scandinavian heritage, or if he got the part because he plays such a great bad guy. Given the Scandinavian surname of his character, Grimsrud, I suspect the former.