The Third Piece of the Puzzle

Around the tenth century, we had simplified word endings. We had this increasing tendency to use a specific word order even though that order wasn't technically required. The big difference between old english and old norse were those inflectional endings. So even if the vikings and the anglo saxons had much of the same basic vocabulary, they couldn't communicate very well without common inflections. Imagine a sentence like this, wild fence chasing the brown while the deer jumped a horse white. Now you know all those words, but the sentence makes no sense. There's no order to it.