For example, could Henry VIII speak Spanish or would he have needed a translator?
Henry VIII spoke English, French, Italian and knew Latin and some Spanish. It was the same with Francis I.
Charles V Holy Roman Emperor spoke German, French, and Flemish, later adding an acceptable level of Spanish.
I think that Elizabeth I spoke French, Flemish, Italian and Spanish. By the time William Grindal became her tutor in 1544, Elizabeth could write English, Latin, and Italian. Under Grindal, she also progressed in French and Greek.