My friend's becoming bitchy?

i have 5 best friends, and it has been that way for a year and a half. one of my friend claims that she inherited an accent from her parents, and it's the weirdest accent i've ever heard, especially when her dad is an indonesian, and her mum is a singaporean! she empasizes all her 'd's and it has only happened LATELY and not when i first got to know her. it has been driving me and my friends NUTS. before the summer holz when we were still at school, she kept on flinging postcards and pamphlets of her summer school in usa in front of our faces, and her mouth has never stopped talking about this fab summer school of hers. my friends are starting to hate her, but i think she can change back to the old girl i used to know. so i attempted to talk this over with her one day alone, but she ended up slamming toilet cubicle doors at school during lunch, crying and screaming, accusing me of calling her an , when i said she was impossible! she'll change, but how? what next?