Slavs live in Central Europe, Eastern Europe, Southeast Europe, Central Asia and North Asia. Present-day Slavic peoples are classified into West Slavs (mainly Poles, Silesians, Czechs, Moravians and Slovaks), East Slavs (mainly Ukrainians, Belarusians, and Russians), and South Slavs (mainly Serbs, Bulgarians, Croats, Bosniaks, Pomak, Torbesh, Gorani, Macedonians, Slovenes, and Montenegrins).
Austrians, Hungarians, Romanians (although 1/3 of Romanian population is made of Slavic population, mainly , Serbians and Bulgarians), Estonians, Lithuanians and Latvians (and these 3 countries have sizable Russian and Poles population, so much so that they make a majority ethnic groups in those countries) live near the Slavic nations but are not Slavs themselves. There are more Slavs than any other ethnic group in Europe. Russians make up the most Slavs, followed by Poles and Ukrainians.
There are many small historic Slavic nations like Lusatia (and Lusatian Serbs, typically referred to as Sorbs, who still live in eastern Germany), Rusyn, Kashubia and others. Russia is now the most powerful and populated Slavic country, but in the 10th century Bulgarians and Czechs were powerful, in 13th and 14th century Serbs were powerful, and in the 16th century Poland was the strongest nation in the area.
The Slavic languages are closely related. The largest similarities can be found within the same group (for example, Polish and Slovak, both West Slavic languages), but similarities exist even between Slavic languages from other different subgroups (such as Bulgarian and Russian).
However, the greatest similarities are between Serbian, Bosnian and Croatian, which are South Slavic languages. They are considered separate by the Bosnian and Croatian governments (the separation is of political nature), but linguistically they are one language- Serbo-Croatian (since Serbian, Croatian, Bosnian and Montenegrin are more similar than those variants of English,[1] German,[2] Dutch,[3] or Hindi–Urdu,[4] and mutual intelligibility between their speakers "exceeds that between the standard variants of English, French, German or Spanish[5]).
Slavic languages are spoken natively by 300 million people and as second or third languages by many more people in countries as far away as Germany and China.