ㄹ까 말다

whether to do it or not

Sets a choice against its opposite: do it, or don't. In five of these eight lines it is immediately followed by 고민하다, and 할까 말까 고민하다 is effectively one phrase meaning 'agonise over whether to': 저도 엄청 이걸 살까 말까 엄청 오래 고민했거든요 'I went back and forth for ages about buying it.' On its own it is the question you are putting to yourself: '아 쟤 오늘 기분 좀 안 좋은 것 같은데.. 말 걸까 말까?'