The Cyrillic alphabet (pronounce /səˈrɪlɪk/; also called azbuka, from the old name of the first two letters) is actually a family of alphabets, subsets of which are used by six Slavic national languages (Belarusian, Bulgarian, Macedonian, Russian, Serbian and Ukrainian) as well as non-Slavic (Kazakh, Uzbek, Kyrgyz and Tajik of the former Soviet Union, and Mongolian). It is also used by many other languages of Eastern Europe, the Caucasus, Siberia and other languages in the past. Not all letters in the Cyrillic alphabet are used in every language that is written with it.