I am conversational in Norwegian (basically Danish in written form) and fluent in English (my native language) Dutch, when you figure out the pronunciation and do a bit of mental figuring, is about 40% for me. I know the gist of what is being written (less of what is being said).
So how much old English from Beowulf do you “get” when it is pronounced. Basically the English had forgotten how to read Old English and it was a Danish/Icelandic linguist who helped figure out the language again.