[1] It represents the Vietnamese sound [ɨ].
As with most special Vietnamese letters, this letter is not well-supported by fonts and is often typed as either ⟨u+⟩ or ⟨u*⟩.
On the Windows default Vietnamese keyboard Ư can be found on where the [ key is on a US English keyboard layout.
Because Vietnamese is a tonal language this letter may optionally have any one of the five tonal symbols above or below it.
This article related to the Latin script is a stub.