> Why did Charles II speak German and no English?
Maybe because Saxony, where a few ... saxons originated from is in the
north of present germany and has always been a german-speaking area. A few
kings of England have come from there in the course of time.
One of the Georges spoke very little english when he arrived, and the
names of a few others in the royal familiy(ies) have a decidedly german
flavour, not least thius Battenburg chap whose Welsh you're wondering about.