Chibnall, Marjorie. Anglo-Norman England: 1066-1166. (Oxford: Basil Blackwell, 1986)

Introduction
"For some centuries the history of the Norman conquest and its aftermath has bee rewrittne in every generation...In the seventeenth century Henry Spelman and Robert Cotton traced the feudal customs that had become legal abuses in their day back to the Norman conquest. They and their fellow antiquaries helped foster the myth of the 'Norman yoke' imposed by an alien king and landlords on free and equal Englishmen: a myth elaborated by reformers and revolutionaries in their day, cherished by romantic nineteenth-century writers like Charles Kingsley and George Barrow, and strong enough to colour the work of some academic historians...

"There is [now] a far keener appreciation of the relevance of European social developments to changes taking place in England and Normandy both before and after the conquest. There is also a clearer understanding of the nature of the gradual assimilation of Norman and English institutions over several decades. Fewer serious historians continue to... align themselves with the English or the Normans, and claim all the political, constitutional or artistic achievements for one side, even if some of the old illusions persist in works of popularization."

"So much has been written on 'feudalism' that some historians now shy away from the word altogether...The basic territorial units, howev er, were not the fiefs of fees (feuda) , the units of knightly tender owing more or less standardized services from which later theorists derived the name. They were the extensive estates of honours of the great barons, centred on a principal residence (caput) which was often a castle, with their nerve center in the honour court. These courst were places for military training, social life, and the transaction of business. In them the military dependants of the great tenants-in-chief bound themselves to their lord in the ceremony og homage and becomae his vassals, undertaking whatever military or other service was customary at the time. There too some received rewards in land and were granted tenure (technically seised) of it in a visible ceremony of enfeoffment; and there they were punished if they failed in their duty to their lord. Courts were frequented too by many household knights, particularly younger sons, who were paid wages and held no land, but served in hope."

Chapter 1: The First Phase of Conquest
Chapter 2: The Moving Frontiers
Chapter 9: Normans and English

Some bits about Rhuddlan, Robert, and Chester:

"Edwin's forfeiture left a vacumn on the Welsh border, and the Conquere's first earl of Chester, Gherbod the Fleming, did not remain long in that most perilous post. By 1071 he had returned to Flanders, and William replaced him with Hugh, vicompte of the Avranchin, a man who throve on warfare and went about, in the words of Orderic Vitalis, with an army rather than a household." (p. 22)

 "Castles were an essential element in the control of the Welsh lands. Even in Edward the Confessor's reign a few Norman settlers had occupied the borders of Herefordshire, and built their mottes in the region of Richard's Castle...Robert established his base at Rhuddlan." (p. 27)

"In 1056, according to the Anglo-Saxon Chronicle, Gruffyd was forced to swear that he would be a loyal and faithful underking to Edward. When peace broke down again in 1063, an army led by Harold found support among the disaffected Welsh princes, and Gruffyd was killed by some of his own men. Harold took oaths of vassalage from Gruffyd's two half-brothers in the north, and the separate southern principalities re-emerged. English pressure along the frontier was renewed. This was the situation inherited by King William, who firmly believed in his right of dominion over Wales. After some of the dispossesed rebels had sought refuge and support among the the Welsh princes, his determination to assert effective authority hardened into a resolve to replace disloyal Welsh leaders by Norman lords wherever possible.
    The lordships established along the Welsh frontiers in the early years of his reign were military authorities, effectively defensive, and poised for further conquest...In the north the initiative was left, after the departure of Gherbod, to Hugh of Avranches, earl of Chester, and his ruthless and agressive nephew, Robert of Rhuddlan. They struck into North Wales across the Dee, and penetrated as far as Conway. According to an entry in Domesday Book, by 1086 Robert of Rhuddlan had obtained from the king a grant of the whole of 'North Wales' (whose exact extent is uncertain) for an annual patment of £40. . . The advance continued into the next reign; Robert established castles at Rhuddlan and Deganway on the river Conway. Hugh probably built those at Bangor, Carnavon and Anglesey before the violence and brutality of the Normans provoked a rising. Robert was killed by a raiding party, probably in 1093, and the advance was halted." (45-46)

On language:

"There is little direct evidence of the languages spoken at different levels of society in the early years of Norman rule. After a year or two Latin gradually replaced Old English as the language of royal writs. . .Bilingualism spread wherever it was needed for everyday business, or for the advancement of the able and ambitious. In the baronial class most men, women and children picked up enough colloquial English to run their households and supervise their estates. . .Some of those who presided in the local courts where English was spoken may have mastered the language thoroughly; other relied on interpreters."
    "Many of the lower clergy spoke only English. One of the miracles recored in the life of Wulfric of Haselby describes how he cured a deaf and dumb boy, who immediately began to speak in French and English. The parish priest who witnessed the miracle complained bitterly that a stranger from far away, who would have been grateful for the gift of speech in a single language, had been granted the use of two, whereas he himself, who had served Wulfric devotedly for many years, had never been given the knowledge of French, and had to stand silent whenever he went to the bishop or archdeacon."