In honor of Oscar night, let's looks at the actors who spent much time and effort perfecting their learned accents to fit their Oscar-nominated roles.  Often times actors work with dialect coaches to learn their character's new voice. Dialect coaches are named as such because they not only work on pronunciation and prosody (accent), but they also target the grammar and vocabulary a character would use. Actors spend countless hours listening to speech models and imitating the lines correctly in order to be believable in their part. Some actors, like Daniel Day-Lewis, even use their dialect full-time off the set in order to prepare for their scenes. Here are my votes for the actors with the best learned dialects which contributed to their Oscar-worthy roles.  

Bradley Cooper as Chris Kyle in "American Sniper" 
Nominated as Best Actor in a Leading Role, and Best Picture

Besides bulking up and learning how to shoot for his role, Bradley Cooper spent four hours a day getting Chris Kyle’s Texas accent just right. “I had so much access to Chris, based on interviews he’d done and video. Hours and hours of him talking,” Cooper told the Navy Times. “I had this huge document that I put on my iPhone and my iPad and I just had it on constantly. I had earbuds on that whole time, just listening to his voice, repeating what he would say.”


Rosamund Pike as Amy Dunne in "Gone Girl"
Nominated as Best Actress in a Leading Role

Pike, a British actress who plays Ben Affleck's missing wife, really struggled with attaining her pristine American accent. "I had a great dialect coach. You work like you're learning a foreign language. We speak the same language, but we also really don't."  The star worked with a dialect coach to learn how to reduce her British accent in exchange for an elite American accent. At one point in the film she even changes into an American Ozarks regional dialect. "It's not just changing your voice, it's changing your whole attitude," she said. "I saw a clip of a talk show this morning and I thought, 'God, I am so English'. You have to lose all that when you are doing a part like this."


David Oyelowo as Martin Luther King Jr. in "Selma"
"Selma" is Nominated for Best Picture

Although snubbed for a leading actor Oscar nomination, Oyelowo gave a spectacular performance as MLK Jr. during the 1965 march in Selma, Alabama to gain equal voting rights. Some ways he prepped for his role included gaining weight, studying films of King, and eroding his British accent. British-born to Nigerian parents, Oyelowo normally speaks with an Oxford accent. He worked extensively with a dialect coach to recreate King’s distinctive Georgian accent. Oyelowo told Backstage Magazine "He's not just from Atlanta; he had formative years in Boston. Then you add in the Southern Baptist preacher...all of these things feed into the way he spoke." Oyelowo continues, "I would argue that even if you were an American actor, there's no one who speaks like Dr. King! No matter who you are, you would have to do a fair bit of work to scale that particular mountain."