For this chain-of-thought reasoning and answer, what was the question?
To answer the question, consider the following: Spoken by over 10 million people, it serves as the official language of the Czech Republic.
A: Czech ( / tk / ; cestina Czech pronunciation : ( tcna ) ) , historically also Bohemian
Q: Czech (/ tk /; cestina Czech pronunciation: ( tcna) ), historically also Bohemian (/ bohimin, b-/; lingua Bohemica in Latin), is a West Slavic language of the Czech -- Slovak group, which is extensively influenced by Latin and German. Spoken by over 10 million people, it serves as the official language of the Czech Republic. Czech is closely related to Slovak, to the point of mutual intelligibility to a very high degree.

Based on this passage, what language do they speak in the czech republic?