When people say 'Old English', they usually mean 'Shakespearean English', but that's actually classified as an early form of Modern English. A lot of Shakespearean English is mutually intelligible with modern English, but most English speakers struggle to understand one paragraph of Shakespearean English without guidance. http://shakespeare.mit.edu/julius_caesar/full.html I've heard that non-native speakers of English can understand that more easily than native speakers. I don't know if it's true or not, but it is true that Shakespearean English becomes much easier to understand if you just ignore word order and try to think of what each word could mean abstractly. This is what Old English really is: http://www.fordham.edu/Halsall/basis/beowulf-oe.asp I can see a few proper nouns in there, but otherwise I can't figure out one word.

This site shows the Lord's Prayer in Old English, Middle English , Early Modern English and Late Modern English. You can decide for yourself ;-) http://www.ruf.rice.edu/~kemmer/Words04/history/paternoster.html

Susan's answer is a good example. I will also show you the same answer, however, in a more simple form: A (VERY) BRIEF HISTORY OF THE ENGLISH LANGUAGE And The Lord’s Prayer It is interesting to compare various versions of a Christian prayer (The Lord’s Prayer) as a good example to see the differences between Old, Middle, and Modern English. Old English (500 – 1000 AD) Fæder ure þuþe eart on heofonum si þin nama gehalgod tobecume þin rice gewurþe þin willa on eorðan swa swa on heofonum urne gedæghwamlican hlaf syle us to dæg and forgyf us ure gyltas swa swa we forgyfað urum gyltendum and ne gelæd þu us on costnunge ac alys us of yfele soþlice. Middle English (1000 – 1500 AD) Some of the words are recognizable to the modern eye: Oure fadir þat art in heuenes halwid be þi name; þi reume or kyngdom come to be. Be þi wille don in herþe as it is dounin heuene. yeue to us today oure eche dayes bred. And foryeue to us oure dettis þat is oure synnys as we foryeuen to oure dettouris þat is to men þat han synned in us. And lede us not into temptacion but delyuere us from euyl. Early-Modern English (1500 – 1800 AD) Late-Modern English (1800 – present) The words are completely intelligible: Our father which art in heaven, hallowed be thy name. Thy kingdom come. Thy will be done in earth as it is in heaven. Give us this day our daily bread. And forgive us our debts as we forgive our debters. And lead us not into temptation, but deliver us from evil. Amen.

Building on what Susan and Richard said, the spoken and written English before about 1600 would be hard to understand by a modern English speaker. Shakespeare (1564 - 1616) is responsible for a huge amount of modern English words, words that he invented. The spelling of a lot of old but still used words changed as well.