context: The official language is Czech, a Western Slavic language which is one of the Indo-European languages. Very similar to the Slovak, Polish and Serbian languages ​​of Lusatia in Germany. Since the Czech Republic joined the European Union in 2004 the Czech language has become one of the official languages ​​of the European Union. Czech linguistics is referred to as Bohemian linguistics relative to the Bohemia region of the Czech Republic.
question: When did the Czechs join the European Union?
answers.text: 2004