Slavic is a distinct language branch which is currently spoken in Central and Eastern Europe, the Balkans, and parts of North Asia.
Until 1000 AD there was a single common Slavic language. After that point, the original language diverged into three main groups, each with its own languages: the Southern group of Serbo-Croat, Slovene, and Macedonian; the Western group of Czech, Slovak, Sorbian, and Polish and its related dialects; and the Eastern group of Russian, Ukrainian, and Belorussian.
Of the Western group, Polish has the largest number of speakers at about 40 million. About 10 million people speak Czech, with its dialects of Bohemian, Moravian, and Silesian. About 4.6 million people speak Slovak, the official language of Slovakia.
The East Slavic languages are Russian, Belorussian, and Ukrainian, with Russian being by far the most widely used.
The South Slavic languages have had a slightly different pattern of development since they are spoken in regions geographically separated from the two other Slavic groups by Romania, Hungary, and Austria, where non-Slavic languages are spoken. The chief South Slavic languages are Bulgarian, Serbo-Croatian, Slovene, and Macedonian.
Writing systems of the Slavic languages have either Latin or Cyrillic alphabets. The Cyrillic alphabet was developed during the 10th century for Slavic-speaking people who belonged to the Eastern Orthodox Church. It is based on Greek and Hebrew letters and was probably devised by two Greek missionaries and brothers, Saints Cyril and Methodius.