My understanding is that when the takeover of 1066 happened the winners of the war moved in and brought their language with them. Since they had all the money and power they got to keep speaking their own language and the locals were the ones who had to adapt. Peasants had pigs, cows, and houses (well hovels really), and continued to use their own (?Saxon) words for these simple things. Many of these words are related to German who had been the previous invaders. Or even Danish (Viking) e.g. church from kirk. The Norman/French nobility had porc, jambon (ham) and mansions and these words eventually filtered down.
This is one reason that English grammer is difficult to learn. It is a mish mash of French and German rules. pretty - prettier - prettiest vs beautiful -more beautiful - most beautiful with the fancier words usually following the French pattern.
Does this help?
