Nowadays, Koppa is not used anymore in any variety, and Che has fully replaced it as the letter with the numeric value 90.

[1] Except for Russian and Serbian, all Cyrillic-alphabet Slavic languages use Che to represent the voiceless postalveolar affricate /tʃ/ (the ch sound in English).

In Russian, Che usually represents the voiceless alveolo-palatal affricate /t͡ɕ/ (like the Mandarin pronunciation of j in pinyin).

The 1955 version of Hanyu pinyin contained the Che for the sound [tɕ] (for which later the letter j was used),[2] apparently because of its similarity to the Bopomofo letterㄐ.

[citation needed] The Latin Zhuang alphabet used a modified Hindu-Arabic numeral 4, strongly resembling Che, from 1957 to 1986 to represent the fourth (falling) tone.