O͘o͘ is one of the six Hokkienvowels as written in the Pe̍h-ōe-jī (POJ) orthography. It is pronounced [ɔ]. Because Hokkien is a tonal language, the standard letter without a diacritic represents the vowel in the first and fourth tone with the fourth and eighth tone always only used in syllables with a syllable stop (i.e. ⟨-p⟩, ⟨-t⟩, ⟨-k⟩, ⟨-h⟩/-ʔ/), and the other six to eight possible tone categories require one of the following tonal symbols to be written above it:
Carstairs Douglas's 1873 Chinese–English Dictionary of the Vernacular or Spoken Language of Amoy used a barred o with curl very similar to the one on the far left of the 4th row of letters from the top of this image to represent the /ɔ/ sound that Pe̍h-ōe-jī (POJ) usually represented with O͘ o͘
The character was introduced by the Xiamen-based missionary Elihu Doty in the mid-nineteenth century, as a way to distinguish the Hokkien vowels /o/ and /ɔ/ (the former becoming ⟨o͘⟩).[1] Since then it has become established in the Pe̍h-ōe-jī orthography, with only occasional deviations early in its usage – one example being Carstairs Douglas's 1873 Chinese–English Dictionary of the Vernacular or Spoken Language of Amoy, where he replaced the ⟨o͘ ⟩ with ⟨ө̛ ⟩ (an o with a curl, similar to that of the English Phonotypic Alphabet),[2] and a second example being Tan Siew Imm's 2016 dictionary of Penang Hokkien, where she replaced the ⟨o͘ ⟩ with ⟨ɵ⟩.[3]
