Tough question.
Is there a site where we can sample these different ai accents?
I really loved the accent when she sang the English version of Youpidou, but I also loved the way she accented certain words in Ella, ella
http://youtu.be/MHJXsio4IqE?t=54
http://youtu.be/Ik5Nh94v7EQ?t=104