Adobe PS: verticallineabovecmb
Unicode: 030D
Script: Latin
Vertical line
History and example of use
The vertical line above has been used by several romanization systems in Taiwan, including Pe̍h-ōe-jī and the Taiwanese Romanization System. It is used above vowels to indicate a specific tone (called tone 8) : a̍ e̍ i̍ o̍ o̍͘ u̍. It is also used in the Standardized orthography of Congo-Kinshasa to indicate mid tone in some languages like Ngbaka Gbaya : a̍ e̍ ɛ̍ i̍ o̍ ɔ̍ u̍.
Design
The angle between the baseline and the vertical line should always be 90 degrees, even in italics or slanted fonts. Otherwise it might be hard to distinguish the vertical line from the acute in some cases.
Fonts should also have the appropriate OpenType feature enabled for a soft dotted i, since the dot of the i is replaced by the combining vertical line.