A report on Old Church Slavonic, Glagolitic script, Cyrillic script and Bulgarian language

The brothers decided to translate liturgical books into the contemporary Slavic language understandable to the general population (now known as Old Church Slavonic).

The Early Cyrillic alphabet was developed during the 9th century AD at the Preslav Literary School in the First Bulgarian Empire during the reign of tsar Simeon I the Great, probably by disciples of Saint Cyril and Saint Methodius, the two brothers who created the earlier Glagolitic script.

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

Both the Glagolitic and Cyrillic alphabets were used until 13th-14th century in Bulgaria.

The term Old Bulgarian (старобългарски, Altbulgarisch) is the only designation used by Bulgarian-language writers.

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.

Byzantine missionaries standardized the language for the expedition of the two apostles, Cyril and his brother Methodius, to Great Moravia (the territory of today's western Slovakia and the Czech Republic; see Glagolitic alphabet for details).

In the languages spoken now where Glagolitic was once used, the script is known as глаголица (romanized as glagolitsa and glagolica, respectively) in Bulgarian, Macedonian and Russian; glagoljica in Croatian and Serbian; hlaholice in Czech; głagolica in Polish; hlaholika in Slovak; and glagolica in Slovene.

Both schools originally used the Glagolitic alphabet, though the Cyrillic script developed early on at the Preslav Literary School, where it superseded Glagolitic as official in Bulgaria in 893.

Until 1945, Bulgarian orthography did not reveal this alternation and used the original Old Slavic Cyrillic letter yat (Ѣ), which was commonly called двойно е (dvoyno e) at the time, to express the historical yat vowel or at least root vowels displaying the ya – e alternation.

In 886 AD, the Bulgarian Empire introduced the Glagolitic alphabet which was devised by the Saints Cyril and Methodius in the 850s.

Slavic languages: Belarusian, Bulgarian, Macedonian, Russian, Rusyn, Serbo-Croatian (Standard Serbian, Bosnian, and Montenegrin), Ukrainian