However, traditional forms of Cyrillic fita (since the 18th century) and Oe are identical, and designers of Unicode's sample font were probably the first ones who split glyphs of the two letters (providing Oe with a horizontal bar and Fita with a tilde-shaped bar inside).

In traditional typography, the shape of the inner line depends on typeface, not on meaning of the letter: the bar in both Oe and fita may either be straight or wavy.

Oe is used in the alphabets of the Bashkir, Buryat, Kalmyk, Karakalpak, Kazakh, Komi-Yazva, Kyrgyz, Mongolian, Sakha, Selkup, Tatar and Tuvan languages.

The letter has also been adopted in the spelling of the Komi-Yazva language, where it represents a close-mid centralized back unrounded or weakly rounded vowel /ɤ̹̈/.

In Kyrgyz, Mongolian and Tuvan, the Cyrillic letter can be written as a double vowel.