Meredith Casey was practicing lines from a play when she got a rude awakening.

When the University of Minnesota/Guthrie Theater acting student spoke a line from Shakespeare’s “Henry IV” — “O, my good Lord, why are you thus alone?”— her instructor stopped her, saying, “You need to not sound like you’re in the movie ‘Fargo.’ ”

The Minnesota accent is a distinct and endearing marker of a true northern upbringing. Those forward o’s and flat a’s, a nasal tone and a singsong lilt are giveaways of a Lake Wobegon heritage and a friendliness that defies subzero temperatures.

But while this unique speech is a point of pride for many Minnesotans, some actors have discovered that it holds them back. To help them land a broader range of roles, more performers are training to adopt a standard, or neutral, sound and erase the accent they grew up with.

“The Minnesota accent has been an interesting challenge for myself and a lot of my classmates, because we speak with almost a smile in our voices,” said Casey, a senior who’s hoping to pursue acting in New York after graduation. When she’s talking “too Minnesotan,” acting teachers tell her: “Back it up; do that again; you sound ridiculous.”

The purpose of downplaying the Minnesota sound isn’t to dis our unique accent, but to prevent the audience’s minds from wandering, said Norah Long, a Twin Cities-based actress who teaches voice and diction.

“The minute you have a sound to your voice that distracts people from what you’re saying, and they’re paying attention to how you’re saying it, you have a problem.

“If one of my students is singing ‘Caro Mio Ben’ with the closed ‘o’ — a dead giveaway — all you can think is, ‘That doesn’t sound right.’ ”

Some of the defining characteristics of the Minnesota accent can be neutralized by relearning where to position certain vowels. Form the “o,” which Minnesotans often emit from the front of the lips, to the back of the mouth. Try it: “No, I don’t know if it will snow.” Loosen up the “a” by saying with an open jaw, “Palm and calm.”

“It takes an intensive commitment to practice,” said Marlene Schoenberg, a Twin Cities accent coach. “It’s like learning the piano as an adult.”

The way Minnesotans talk can be traced to the influence of Scandinavian and German immigrants, who shaped not just sounds, but phrases, such as “come with” (a preposition-ending faux pas in any other region).

“Way back when people came to the Upper Midwest and they were speaking those settlement languages and learning English, they would map a feature onto the new language,” said Minnesota native John Spartz, a professor at the University of Wisconsin-Stout in Menomonie, whose dissertation focused on the “come with” construction.

“It’s what you hear when you hear people who are second-language English speakers use a remnant of their first language,” he said. “That’s what creates accent.”

Some vocal coaches hypothesize that climate has something to do with how Minnesotans sound, too.

“Your language is connected to the land that you’re in,” said Lynn Singer, a New York City-based voice teacher for actors. With Minnesota getting as cold as it does, Singer hears a “lockjaw effect” in speakers, who don’t use the full range of motion of their lips and jaws. “You’re not wanting to get too much cold air into your mouth.” (The theory is unproven, Spartz said.)

But for many Minnesotans, the accent is something to be proud of.

“Our identities are intimately related with our dialect, which is intimately related to our accent,” Spartz said. “It tells people about where we grew up, who our friends are, what we value. The accent is part and parcel with the culture.”

Alrighty, then

The credit (or is it blame?) for popularizing the Minnesota sound outside our state’s borders goes to the 1996 film “Fargo.”

“That was the first time the Minnesota/Upper Midwest dialect was really put on the map in terms of something to be made fun of, and of course, Minnesota people have a hard time laughing at themselves,” said Michelle Hutchison, a Twin Cities actress who used her Minnesota accent in several film and television roles, including as a high-priced escort in the Coen brothers’ famed film.

“When ‘Fargo’ came out, a lot of people said, ‘Oh, we don’t talk like that.’ But some of us do, and that’s OK.”

Comedian Andy Erikson, who grew up in Blaine and Ham Lake, also has been using her native accent to her advantage in the three years she’s been working in California. Her accent comes out most when she’s onstage telling jokes.

“When I get really excited and into something, I start to sound more Minnesotan,” she said.

Using the word “pop” for a carbonated beverage or asking for a “bag” (pronounced “baaayg” in Minnesotan) at the grocery store becomes fodder for her stage delivery and helps her stand out from the crowd, she said.

“I try to come off being nice and sweet, so I think it helps to have a Minnesota accent,” said Erikson, who is performing at Minneapolis’ Comedy Corner Underground this weekend. “I can play it up when I’m saying a joke that’s not so nice. I get away with more things, perhaps.”

Yet for her recurring role on Fox’s “Scream Queens,” she tones it down. “You don’t want to sound out of place,” she said.

Stronger in the spotlight

The spotlight has a way of bringing out stronger accents, agreed Holly Collison, a vocal coach at the Guthrie. In addition to working with actors, she has trained business professionals from around the state on their presentation skills and noticed how thick their accents get when they are presenting.

“It’s not bad to have a Minnesota accent, but it’s important to notice how when people become very nervous, it becomes amplified,” she said.

Hutchison, who boasts a strong Duluth accent on an episode of Maria Bamford’s Netflix series “Lady Dynamite,” said she relies on her ear to adopt more neutral speech patterns. But she has been stopped while recording a voice-over for a national commercial and told to fix a word or two.

“As an actor, you’re going over your work with a fine-toothed comb to correct those regionalisms you pick up,” she said. “Your ear hears what it hears, so you’re always building a broader awareness.”

Reid Emmons, a U/Guthrie sophomore, has been training to lose his Minnesota accent since he was in high school debate class, when one of his debate coaches mocked him for a long “o.”

He’s taken courses at the U in accent work and pronunciation, but that “o” continues to betray his Eagan upbringing. He tasks friends and family members with calling him out every time he says it.

“It’s the thing we’re made fun of for the most,” he said, “and it’s also the thing that’s most real.”