Thanks for the links Emily.
"I have gotten
You (singular) have gotten
He/she/it has gotten
We have gotten
You (plural) have gotten
They have gotten"
That's just awful. The lack of specification makes it sound like baby talk. Its like Dutch and Afrikaans.
I would tend to question Woodbury's conclusions. Isn't what she is trying to do a big no-no in linguistics? Making assumptions of language rules based on a very few examples? Authors make up all sorts of terms or use obscure words to suit their own purposes but they should not be taken as a definitive guide to historical language use. There are plenty of examples in modern day Harry Potter novels. But you would hope that someone years from now would not use it to justify that we play a game called quidditch!