Church Slavonic language
The Church Slavonic language (ru: церковнославя́нский язы́к) is the liturgical language of the Russian Orthodox Church. Historically, this language is derived from the Old Church Slavonic language.
The Church Slavonic language is written with Cyrillic alphabet while using a lot of diacritical signs. Currently the computer support for this language is very poor, so people have to use some ad hoc solutions.
