Eivind, as far as I know what we've got is such in a corrupted state, and mostly handwritten. If you take handwritten Icelandic sagas and their normalised counterparts, you'd argue that you're talking about two different languages. I was told that it all depended on the one copying the scripts and how was he trained. Sometimes they wrote 'as they heard' or referring to a particular dialect...
Italian was written in the same way, and you often find words with k's and other unconventional signs in the manuscripts...
Don't want to argue any more on this, otherwise it'll be an endless thread. I'll stick to what it will be decided.