母音 /ʊ/ 是高後母音(high back vowel)。發音時，嘴唇圓形，舌頭在口腔裏的位置是中高位，呈放鬆狀態。
母音 [ʊ] 發音的拼讀方式有下列幾種可能性：
u
＜子音 + ʊ + 子音＞：bush [bʊʃ], push [pʊʃ], put [pʊt]
v
＜-o-＞：woman [´wʊmən],
wolf [wʊlf]
w
＜-oo-＞：book [bʊk], look [lʊk], hook [hʊk]
x
＜-oor-＞：poor [pʊr]
y
＜-ou-＞：should [ʃʊd], would [wʊd], could [kʊd]
z
＜-u-＞：bull [bʊl], full [fʊl], bullet [´bʊlɪt]
{
＜-ue-＞：continue [kən´tɪnjʊ]、rescue [´rɛskjʊ]
|
＜-ure-＞：assure [ə´ʃʊr]、sure [ʃʊr]、lure [lʊr]