Czech, historically known as Bohemian, is a West Slavic language of the Czech–Slovak group, written in Latin script. Spoken by over 12 million people including second-language speakers, it serves as the official language of the Czech Republic. Czech is closely related to Slovak, to the point of high mutual intelligibility, as well as to Polish to a lesser degree. Czech is a fusional language with a rich system of morphology and relatively flexible word order. Its vocabulary has been extensively influenced by Latin and German.