I suspect actual spoken Anglo-Saxon (as by the common people, not the nobility) would probably more easily understood by a modern Dutch, Frisian, or Low German

I suspect actual spoken Anglo-Saxon (as by the common people, not the nobility) would probably more easily understood by a modern Dutch, Frisian, or Low German speaker than by a modern English speaker. Our language has been heavily heavily influenced in the interim first by Old Norse/Danish and then (a huge amount) by Norman French. I actually have an easier time with Anglo-Saxon than Chaucer, personally. Middle English has bizarre inconsistent orthography, and is full of French loans. While written Anglo-Saxon is pretty consistent and some of the vocabulary and grammar makes sense to me as someone who studied German a bit. Old English is a really beautiful language. But in general what we have in written records is what was written by the literate elites, not regular folk. So it's really hard to say what it would be like to be dropped into the villages of 15th century England.