Etymology

From vì (爲, "because, for") and sao ("what").

Pronunciation

• (Hà Nội) IPA^(key): [vi˨˩ s̪aːw˧˧]
• (Huế) IPA^(key): [vɪj˧˧ ʂaːw˧˧]
• (Hồ Chí Minh City) IPA^(key): [vʲɪj˨˩ ʂaːw˧˥]