The child opened their mouth wide and started crying.
Tips
usage
咧 almost always appears with 嘴 (zuǐ, mouth). 咧嘴笑 = grin, 咧嘴哭 = cry with mouth wide open. The mouth shape is the key image — stretched wide, either in joy or pain.
grammar
Also read as lie (neutral tone) in some dialects as a sentence-final particle similar to 了, e.g., 好咧！(Alright then!). This usage is informal and regional.
