A good way to look at this is to take a look at the sound changes that occurred from Old English to Middle English. 1114 was around the very end of what we typically call Old English, and 1314 is fairly-early Middle English, enough time for some Norman influence to seep in, but not a whole lot, and the Great Vowel Shift wouldn't even begin for another couple decades.

Relatively-little grammatical changes happened in those two centuries. The most notable things to happen were a reduction in the case system and a loss of the dual number except in pronouns, plus the introduction of new vocabulary from the Norman ruling class. All-in-all, these are fairly-insignificant, and wouldn't hamper communication significantly. Most-likely, the person from 1314 would have an easier time understanding the person from 1114 than vice-versa (mostly due to the differences in vocabulary), but it wouldn't be particularly drastic.

This isn't very surprising, though. Except in very extreme cases, 200 years is not particularly-long as far as a language goes. Here is the intro to a well-known poem written 200 years ago, and while there is probably some vocabulary you don't know (or maybe aren't too familiar with), it's still very-understandable:

O say can you see by the dawn's early light,

What so proudly we hailed at the twilight's last gleaming,

Whose broad stripes and bright stars through the perilous fight,

O'er the ramparts we watched, were so gallantly streaming?

And the rockets' red glare, the bombs bursting in air,

Gave proof through the night that our flag was still there;

O say does that star-spangled banner yet wave,

O'er the land of the free and the home of the brave?

If you were to hear this spoken in dialects contemporary to the writing, you would probably have absolutely no trouble understanding it in most cases, as partially-attested by the fact that it still rhymes fairly well.