Topic summary
Yi (Cyrillic)

Yi or Ji (Ї ї; italics: Ї ї) is a letter of the Cyrillic script. Yi is derived from the Greek letter iota with two dots.
It was the initial variant of the Cyrillic letter І/і, which saw change from two dots to one in the 18th century, possibly inspired by similar Latin letter i. Later two variants of the letter separated to become distinct letters in the Ukrainian alphabet.
It is used in the Ukrainian alphabet, the Pannonian Rusyn alphabet, and the Prešov Rusyn alphabet of Slovakia, where it represents the iotated vowel sound /ji/, like the pronunciation of ⟨yea⟩ in "yeast". As the historical variant of the Cyrillic Іі, it represented either /i/ (as i in pizza) or /j/ (as y in yen).
In various romanization systems of Ukrainian, ї is represented by Latin letters i or yi (word-initially), yi, ji, or even simply ï.
It was formerly also used in the Serbian Cyrillic alphabet in the late 18th and early 19th century, where it represented the sound /j/; in this capacity, it was introduced by Dositej Obradović but was eventually replaced with the modern letter ј by Vuk Stefanović Karadžić.
In Ukrainian, the letter was introduced as part of the Zhelekhivkaorthography, in 's Ukrainian–German dictionary (2 volumes, 1885–86).