Cyrillic

The Cyrillic script is a writing system used for a wide range of languages in Eastern Europe, the Caucasus, and Central Asia. It was developed in the 9th century in the First Bulgarian Empire by the followers of the Byzantine missionaries Saints Cyril and Methodius to translate liturgical texts into Old Church Slavonic. The script is based on the Greek alphabet and adds new letters to represent Slavic sounds not found in Greek. Over time it became the standard script for literary and religious works across many Slavic-speaking regions.

Cyrillic spread with Christianity and state institutions, becoming the literary norm in areas of the former Byzantine and Kievan realms. Today it is the official or predominant writing system for languages including Russian, Ukrainian, Belarusian, Bulgarian, Macedonian, and Serbian (which also uses a Latin variant). It is also used for numerous non-Slavic languages, such as Kazakh, Kyrgyz, Tajik, Mongolian, and several languages of the former Soviet Union, each with its own local letter extensions to represent native sounds.

Orthographic reforms over the centuries produced various national alphabets, and the modern Russian alphabet contains 33 letters. Different languages that use Cyrillic may add or modify letters to suit their phonology. In computing, Cyrillic text is represented in Unicode, primarily within the Cyrillic blocks (and extended blocks) to cover both contemporary and historic letters. The script remains a central element of writing systems in many countries and continues to adapt to linguistic needs and technological contexts.