to perform certain involuntary bodily actions (as in 打喷嚏 dǎ​pēn​tì, 打哈欠 dǎ​hā​qian, or 打嗝 dǎ​gé)

(sound) the sound of laughter; also used as an exclamation to express joy or, occasionally, sarcasm and anger

A suffix attached to a word to form a retroflex ending, often indicating a small size, a sense of familiarity, or turning a word into a noun.