Comparing 10 new words in English with their French equivalents

1. Parliament- from French parlament
2. Theology- from French theologie
3. Plaintiff- from French pleintif
4. Peace- from French pais
5. Sergeant- from French sergent
6. Sapphire- from French saphir
7. Diamond- from French diamant
8. Poultry- from French pouletrie
9. Lettuce- from French laitues
10. Tragedy- from French tragedie 
It seems that for the most part more letters were added to the words as they became English words. However, in some cases the endings became simpler. In two cases an -ie ending became a -y ending. Unusual (to English, of course) spellings and vowel combinations were also altered, such as in the case of poultry. Originally as pouletrie, there were many more vowels and it is unusual in English to have the sounds so spelled out as in the middle to end of the word (etrie). In this case, the word became simpler. Similarly, in the case of plaintiff unusual spellings were eliminated. In the English language the vowel combination "ei" is far less popular for the "ay" sound than the vowel combination "ai." Therefore the spelling was altered to create a more "English" spelling of the word, as was also done for lettuce.

http://www.etymonline.com/index.php
http://french.about.com/od/vocabulary/a/french-english-spelling-equivalents.htm


http://en.wikipedia.org/wiki/File:Origins_of_English_PieChart.svg