I was more thrown off by her gigantic-sized lips. 
The size is alright. What weirds me out is how puckered up they are, like a duck's beak.
You want gigantic lips? That's Vivienne. Her mouth covers up half her face, I swear. I guess that is what the devs believe black people look like.
Mother Giselle's accent is at least less atrocious than Marjolaine's in DA:O! Now THAT accent was painful to listen to.
She sounds like she's doing a cat impression. Listen closely and you'll hear Marjolaine purr.
I don't know. Would't it be a bit immersion breaking if they spoke French in "not-France" Orlais and Spanish in "not-Spain" Antiva? That's likely why they don't do that. I'm guessing they use the accents to give the impression that the characters are from a different nation with its own language and flavor, but since Orlesian isn't really French, they don't go all the way into the language itself.
Vicento (Feynriel's father) says "maldición!" when Hawke shows that he's a mage too.
And of course, let's not forget about the Felicissima Armada.
Glad I'm not a native English speaker when it comes to stuff like this. Ignorance is bliss 
I cant even spot the difference between american and english unless I really pay attention, that or if the word "Cant" is used.
People are like, "Where is Harley's Brooklyn accent in the new movie?" and I'm all "I never knew she had that. Whatever it is".