氣自己跑出來
核心畫面最直接的一組：沒有人做什麼，氣就上來了。動詞不接受詞，名詞就是那一聲。
verb · B1
To let air come up loudly from your stomach and out through your mouth, usually after eating or drinking.
打嗝（打飽嗝）
核心畫面
One way to hold this word: gas trapped in a closed space, pushing upward, until it finds the opening and comes out with a short noise. The word is that noise — it was made out of the sound. From there English asks only one question: did the gas come out by itself, or did somebody help it out?
可以想成一團被關住的氣，往上頂，最後找到出口，「啵」的一聲跑出來。這個字本身就是那個聲音——它是照聲音造出來的，所以…更多收起
可以想成一團被關住的氣，往上頂，最後找到出口，「啵」的一聲跑出來。這個字本身就是那個聲音——它是照聲音造出來的，所以短、重、一個音節。剩下的用法只差在一個地方：那口氣是自己跑出來的，還是有人幫它跑出來的。自己跑出來，是打嗝；有人幫忙，受詞就出現了——可能是寶寶，也可能是一個發酵中的罐子。From the word’s history
Recorded as originally American English and of imitative origin: the word was made out of the sound itself, which is why the noun and the verb are the same short syllable.
來源記錄說它出自美式英文，而且是擬聲字：這個字就是照那個聲音造出來的，所以名詞和動詞同形，都是一個短音節。
Wiktionary entry for 'burp' (etymology_text: 'Originally from American English, of imitative origin.'), supplied in this packet
Two branches
幫忙把氣放掉
同一團氣，但這次有人出手。句子多了一個受詞，而且受詞是「氣被放出來的那一方」，不是打嗝的人。
verb · B1
To help a baby let air out of its stomach, usually by holding it upright against your shoulder and gently rubbing or patting its back.
幫（嬰兒）拍嗝