Czech dialects and Common Czech. The modern Czech language (Standard Czech) is generally based on the medieval literary Czech (approximately its state in the 16th century). It is practically only a formal, bookish language used in media and people don't use it in friendly contacts. The language of normal communication is the so-called Common Czech, which is actually the current form of the dialect of Central Bohemia and especially Prague. This "bilingualism" came into being in the 19th century, during the era of the Czech national revival that led to the renaissance of Czech literature after 200 years of its hard suppression. Since the speech of contemporary ordinary people was uncultivated, the revivalists started to use the language of medieval literature. This language norm later became official, yet the speech of ordinary Czechs remained the same and continued in its development. Today some features of Common Czech slowly penetrate into the official language and the differences partly decrease. Common Czech has also largely pushed out all former Bohemian dialects and became the only tool of non-formal communication in Bohemia (although some regional differences may exist).