A report on Slavic languages and Old Church Slavonic

The South Slavic languages are one of three branches of the Slavic languages.

The first South Slavic language to be written (also the first attested Slavic language) was the variety of the Eastern South Slavic spoken in Thessaloniki, now called Old Church Slavonic, in the ninth century.

The two languages have several characteristics that set them apart from all other Slavic languages; changes include the elimination of case declension, the development of a suffixed definite article and the lack of a verb infinitive.

Old Bulgarian (9th to 11th centuries, also referred to as "Old Church Slavonic") – a literary norm of the early southern dialect of the Proto-Slavic language from which Bulgarian evolved. Saints Cyril and Methodius and their disciples used this norm when translating the Bible and other liturgical literature from Greek into Slavic.

The Cyrillic script is a writing system used for various languages across Eurasia and is used as the national script in various Slavic, Turkic, Mongolic, Uralic, Caucasian and Iranic-speaking countries in Southeastern Europe, Eastern Europe, the Caucasus, Central Asia, North Asia, and East Asia.

These additional letters were used for Old Church Slavonic sounds not found in Greek.

It is the most spoken Slavic language, and the most spoken native language in Europe, as well as the most geographically widespread language of Eurasia.

The vocabulary (mainly abstract and literary words), principles of word formations, and, to some extent, inflections and literary style of Russian have been also influenced by Church Slavonic, a developed and partly Russified form of the South Slavic Old Church Slavonic language used by the Russian Orthodox Church.

They originally represented phonemically the "ultra-short" vowels in Slavic languages, including Old Church Slavonic, and are collectively known as the yers.

Proto-Slavic (abbreviated PSl., PS.; also called Common Slavic or Common Slavonic) is the unattested, reconstructed proto-language of all Slavic languages.

This language remains largely unattested, but a late-period variant, representing the late 9th-century dialect spoken around Thessaloniki (Solun) in Macedonia, is attested in Old Church Slavonic manuscripts.

The East Slavic languages constitute one of the three regional subgroups of Slavic languages.

After the conversion of the East Slavic region to Christianity the people used service books borrowed from Bulgaria, which were written in Old Church Slavonic.

Slovene is an Indo-European language belonging to the Western subgroup of the South Slavic branch of the Slavic languages, together with Serbo-Croatian.

Like all Slavic languages, Slovene traces its roots to the same proto-Slavic group of languages that produced Old Church Slavonic.

The Bulgarian and all the Slavic churches use the title Pravoslavie (Cyrillic: Православие), meaning "correctness of glorification", to denote what is in English Orthodoxy, while the Georgians use the title Martlmadidebeli.

A major event in this effort was the development of the Cyrillic script in Bulgaria, at the Preslav Literary School in the ninth century; this script, along with the liturgical Old Church Slavonic, also called Old Bulgarian, were declared official in Bulgaria in 893.

From Proto-Balto-Slavic, the later Balto-Slavic languages are thought to have developed, composed of sub-branches Baltic and Slavic, and including modern Lithuanian, Polish, Russian and Serbo-Croatian, among others.

PIE > Pre-Balto-Slavic *eźHom > (Winter's law) *ēˀźHom > Proto-Balto-Slavic *ēˀźun > Common Slavic *(j)azъ́ > OCS azъ, Slovene jaz.