12个单元音的音标如下：/ɑ:/ /ɔ:/ / ɜ:/ /i:/ /u:/ / ʌ/ /ɒ/ /ə/ /ɪ/ /ʊ/ /e/ /æ/发音时，舌位、唇形、开口度始终不变的元音叫单元音。

单元音发音时可按舌面隆起的位置分为前元音，后元音和中元音三类。发前元音时舌的最高点在口腔的前部；发后元音时，舌的最高点在口腔的后部；发中元音时舌的最高点在口腔的中部。扩展资料：以英语元音为例分为：

1、前元音: [i:] [ i] [ e ] [æ]2、中元音: [ʌ][ə:][ə]3、后元音: [ɔ] [ɔ:] [u:] [u] [a:]气对应的英文为：[i:] sea, he, see, piece, ceiling, street, beef, these, week, meat, agree[ɪ]sit, build, miss, myth, palace, between, if, give, busy, gym[e] bed, desk, head, anything, many, again, special, heavy, weather, whether, friendly[æ] bad, land, bank, stamp, pal, Canada, taxi[a:] car, fast, class, plant, calm, aunt[ ɔ] hot, want, wallet, wash, what[ ɔ:] door, more, sport, ball, warm, author, court, bought, caught[u:] who, blue, soup,[u] look, put, women, could，good[ ʌ] cup, come, blood, rough[ ə:] girl, work, serve, nurse[ə ] cadre, ago, forget, polite, dollar, doctor, famous, Saturday