Perception of English listeners on Vietnamese vowels contrasting in rounding

This study investigated into how English listeners from Midland U.S. perceived Vietnamese back vowels contrasting in rounding. The words were produced by Northern and Central Vietnamese speakers. The results showed that Vietnamese vowels [o] and [u] was assimilated to English [oʊ] (77%) and [u] (69%) respectively. [ɤ] and [ɯ] were not assimilated to any English vowels.