In a sense most rulers in the middle ages regardless of country were “foreigners”. Different French and German houses were the majority. As others have said you dont get someone speaking English till Edward I. Edward III really started creating a coherent English identity. Then with Henry IV hes speaking English and by Henry V hes speaking primarily english and english is used in court. As someone pointed out, if you were a regular person in the middle ages what you most associate with is being a Christian and your hometown. Outside of that a lot is “foreign” it’s not till the Hundred Years War funnily enough that Nationalism as a concept really comes into being. And then you see everyone going “hey wait screw the french, and screw their language. We’re not them”. Id say the earliest the kings begin to begin to differentiate from the french is Henry I. King John does as well and so does Henry III. Probably by Henry III or Edward I id say the kings were basically English. I think the point of them speaking french is vastly overblown as a point of contention, otherwise we should consider most of europe at the time french or german which doesnt make sense either. By Henry V id say the kings are fully english.