Eastern Slavic:
* Russian: The most widely spoken Cyrillic language, with over 250 million speakers.
* Ukrainian: Around 45 million speakers.
* Belarusian: Around 10 million speakers.
* Rusyn: A minority language spoken in parts of Ukraine, Slovakia, and Romania.
South Slavic:
* Bulgarian: Around 8 million speakers.
* Serbian: Around 10 million speakers, often using both Cyrillic and Latin alphabets.
* Macedonian: Around 2 million speakers.
* Montenegrin: Around 600,000 speakers, uses both Cyrillic and Latin alphabets.
Other:
* Kazakh: The official language of Kazakhstan, with over 15 million speakers.
* Kyrgyz: The official language of Kyrgyzstan, with around 5 million speakers.
* Uzbek: The official language of Uzbekistan, with over 30 million speakers, primarily uses the Latin alphabet but also uses Cyrillic in some contexts.
* Tajik: The official language of Tajikistan, with around 8 million speakers.
* Turkmen: The official language of Turkmenistan, with around 6 million speakers.
* Mongolian: The official language of Mongolia, with around 3 million speakers.
* Serbo-Croatian: A language spoken in Serbia, Croatia, Bosnia and Herzegovina, and Montenegro, which uses both the Cyrillic and Latin alphabets.
Historical:
* Church Slavonic: A liturgical language used by the Eastern Orthodox Church, it is based on Old Church Slavonic, which influenced other Cyrillic languages.
* Old Church Slavonic: The language of the First Bulgarian Empire and the basis for many Cyrillic languages.
Note:
* Some languages, like Serbian and Montenegrin, use both Cyrillic and Latin alphabets.
* In some countries, like Kazakhstan and Uzbekistan, Cyrillic is being replaced by the Latin alphabet.
* There are numerous other languages that have been written in the Cyrillic alphabet throughout history, but they are not in active use today.
This list represents the main languages currently using Cyrillic. The exact number of speakers and the use of Cyrillic may vary depending on region and historical context.