We usually heard these statements
• “Lấy cái tay ra coi!” (Take your hands off!)
• “Ngon làm coi!” (I dare you do it!)
• “Cho miếng coi!” (Give me some!)
• “Nói nghe coi!” (Tell me!)
• It is possible to see (“coi”) what is being performed (“làm thử”), but how can an utterance (“nói”) be seen?
…
“Coi” originally means watching or seeing (“xem, trông”), but in these utterances, it plays the role of an expletive word in requests or enquiries.
*Source: varied
