There's an excellent discussion of the fake Old English in Paul Kingsworth's novel The Wake on The Toast.

Against the recommendation of medievalists I trust, I bought this novel and read about 100 pages before giving up on it. It wasn't that I found the pseudo-Old English incomprehensible. Once upon a time, Old English was my primary field of study, and I got what Kingsworth was trying to do.

Nor was I offended by the inaccuracies in the pseudo-Old English. I know quite well what sort of bastardizing compromises you have to make when you're trying to give a modern audience a taste of something Old English while staying at least vaguely within the bounds of intelligibility.

What made me put down the book was the same thing that comes in for extensive criticism in The Toast conversation: the use of swearing. It was so inauthentic, not just etymologically but so much just a direct importation of modern attitudes towards cursing, that Kingsworth completely alienated me. After all, he claims that the language is deployed as an alienating device, to drive home the point that the people and time are other. Yet beyond the linguistic surface, it doesn't seem that Kingsworth has really studied the cultural attitudes of Anglo Saxon people at all.