My ear's honestly. There is a distinct pattern of speech for people in Northern Minnesota. People talk very similarly in Canada as well, just as people in the South have a very distinct vocal quality. Ms. Theron fluctuated between a neutral American midwest accent for some scenes and a Northern accent for others. It made the performance uneven at parts. I think she did have a very emotional role, and she did her job well enough, but accents are an all or nothing job so if you do it, do it right. I personally found the film too contrived and manipulative though and would rather like to dismiss it entirely.

As for Geisha perhaps it was more a complaint of broken English. Zhang Ziyi speaks in the film like she can't speak English and had to learn all her lines phoenetically (spelling?). There is none of the vitality and beauty of her words that she carries in many of her Asian films. Then again I heard that many people in China complained about her Mandarin in Crouching Tiger, so perhaps I'm not a particular judge. I recognize that we each have our personal tastes, but I'm sorry to say that two of your three favorite movies of the year I would say were two of the weakest I saw. Then again you may very well say the same about Sin City, Serenity, or Pride and Prejudice films that I particularly loved and felt deserved more Oscar attention (although I can't say I'm surprised Sin City and Serenity were ignored).

btw I'd like to pat myself on the back for pointing out the merits of Reese Witherspoon's performance long before she became a favorite for an Oscar.