After the Norman Conquest, how and when was "English" restored as the language of the noble cl?

The thing about English is that the language absorbed both Norman French words and Anglo Saxon to make the language we know today. A fine example is in meats - in the early medieval period the peasants raised the animals whilst the French nobility ate the produce. So we rear 'cows' (AS) but eat beef (boeuf, FR), or raise pigs (AS) but eat ham (jambon FR). Remember that by the reign of Richard II English was, however, becoming the received language of the country - Chaucer wrote The Canterbury Tales in Middle English.