Phonologically, I believe the only differences from Modern English are the inclusion and lack of certain vowels, e.g., /y/ and /œ/, the presence of vowel length, the presence of /x/, and it's possible that the /r/ be trilled. Not entirely sure, depends on your teacher, I guess.
Vocabulary wise, this was the beginning of the mass importation of French (Latinate) words so they may look different and may have more common, for the time, germanic counterparts. e.g. sight instead of vision.
Grammatically, I believe there are more inflections. Not Sure
Oh yeah, also the presence of /ç/ which was lost in Modern English. (But it reappears in modern English, although I only consistently pronounce it in the word human, /çjumɛn/.)
Native: English (NW American)
Beginning: Arabic (MSA/Egyptian)
Some day: German