This is also where the cultural taboo of four-letter words originates.
The Normans wanted their Anglo-Saxon subjects to say urinate instead of piss, coitu instead of fuck, defecate instead of shit.( "Non, non, non, you Saxon pig!" "We do not piss in the bushes! We urinate in the bushes!""That's what I said mate! I just marinated the bloody bushes!" ). In the aftermath of the Conquest, the Normans stayed cooped up in their castles, for fear of being stabbed or beaten to death by the peasants. And ultimately, the Normans became more Anglo-Saxonized, than their subjects became Normanized.Initially, the Normans wanted the English to drink more wine, and less beer.But the English soon had them drinking less wine, and more whiskey, beer, and gin.

The English royalty used to speak German.

same exact thing in Russia....a completely phonetic language, and when i took a course and sounded out my words that were written in Cyrillic they had a French accent built in! Fun!

Of course it was. The Normans were vikings who, 300 years earlier, had been granted a vast swathe of France in return for leaving the rest of France alone.
They had "gone native", speaking French with a bit of Danish thrown in. When the Normans conquered England, they became the new aristocracy. It took another 300 years before they "went native" again.
However, the language of diplomacy remained French until very much later.