How can I add an Old English dictionary to Dictionary?

Is there a way to add an Old English dictionary to the Dictionary app? I would like to three-finger-tap a word that's Old English and have it translate it for me.

For pure adventure I want to read Beowulf in its original Old English form. I was all excited to use Dictionary to help me through each word, and was kinda surprised when it didn't know practically any word in it at all.

If I open Dictionary and search a word (such as HWÆT), it does actually return some related words because their origin is the Old English word.

Any ideas?