The Catholic Church made Latin the universal language of Western Christendom (hence why they're called Latins by the Byzantines). All nobles would have a basic knowledge of Latin and many in French, Greek would be ignored as the Renaissance has not yet occurred. 

In the East itself most would speak Greek and the learned would speak Latin; Hebrew would be known by the Jews and scholars and Arabic by the Jews, Muslims and maybe some Eastern Christians.

In England they would speak Saxon (a bastardised German) or Norman French depending on which rank they come from.