Answer:
Old English is a form of English spoken from roughly 450 CE through 1150 CE. Because English spelling is very conservative, some common Old English words are still recognizable, but the language has changed considerably in pronunciation and vocabulary, though somewhat less in grammar. Consequently, reading and understanding Old English requires study similar to learning any foreign language. There are many resources online for learning Old English. One of the more accessible is The Electronic Introduction to Old English, by Peter Baker, hosted at the University of Michigan site on the link below.