While it sounds like one vowel sound, it's actually a diphthong, which means it's a combination of two vowel sounds. In this case, the "ou" sound transitions from the sound of "ow" (like in "cow") to the sound of "oo" (like in "moon").
While it sounds like one vowel sound, it's actually a diphthong, which means it's a combination of two vowel sounds. In this case, the "ou" sound transitions from the sound of "ow" (like in "cow") to the sound of "oo" (like in "moon").