# 2.1.8. ɑː/ɔː
这一对元音在发声的时候，嘴唇动作非常明显，要在嘴唇形成一个小的圆形之后才开始发音。
When pronouncing this pair of vowels, the lip movement is very noticeable. It's important to form a small circle with lips before beginning to vocalize.
在 CEPD 里，美音 ɑː 实际上对应的是英音里的短元音 ɒ。在美音里，ɑː 可以被理解为是个半长元音。
In the Cambridge English Pronouncing Dictionary (CEPD), the American English vowel sound ɑː actually corresponds with the short vowel sound ɒ in British English. In American English, ɑː can be thought of as a *semi-long* vowel.
与英音的 ɒ 相比，美音的 ɑː 会嘴巴张得更大一点，读得更长一点，听起来更像 ɑ，但口型略圆。比如，*dog*, 英音是 dɒg, 美音却是 dɑːg；而 *God*, 英音是 gɒd，美音同样相对更长一点，gɑːd。
Compared to the British ɒ, the American ɑː is pronounced with a slightly more open mouth, held a bit longer, and sounds more like ɑ. However, the shape of the mouth is slightly rounded. For instance, for the word *dog*, in British English, it's pronounced as dɒg, while in American English, it's pronounced as dɑːg. Similarly, for *God*, it's gɒd in British English, but in American English it's elongated to gɑːd.
另外，在重读音节里，ɔː 可能会被美国人儿化，读成 ɔːr ，更像是双元音 ɔər。比如，*more* mɔːr。
Additionally, in *stressed* syllables, ɔː might be rhotacized by Americans to sound like ɔːr, resembling the diphthong ɔər, for example, *more* mɔːr.