Expression used by many Asians, to exclaim frustration, annoyance, or stress, used in particular by people of Malaysia, Vietnamese, Singaporean, Chinese, Taiwanese, and in some extent Thai nationalities, but isn't limited to these nationalities and/or countries. See aiyoh
Wei Ling: How come you got 81, Nadya?
Nadya: Stupid mistake lah. Aiyah, what will ma say now?