d'oc or au contraire

Continuing my want for accompaniment and stares in stopped traffic—of which there is a good deal of and part of my motivation, although it’s getting harder and harder to tell blathering to one’s self from blathering to someone far distance or shouting orders at one’s communication devices but perhaps the call and response pace of a foreign language audio-textbook looks less than natural, during my commute—which sometimes can take a significant amount of time, I try to recite at least the introductory lessons of the library’s collection.
I am preparing for our next vacation and always figure it is worth risking a little confusion or letting something learnt expire in the meantime due to disuse to exercise the mouth. I think American English especially is not a very enunciative one and the work-out and exaggeration are necessary for any progress—whatever might stick during these sessions, since I am paying more attention to the road. I knew the German interjection Doch! for really or uh-huh, but while listening to the parallel structured lessons, I learned that the come-back phrase is really a formal and polite contradiction of a question framed in the negative, akin to yes indeed.
The French equivalent is si as opposed to the usually oui, which I never appreciated before. Both languages have two ways of saying yes and one word (form) for no.   English, it turns out, once utilized four forms that followed this pattern and were appropriate responses, depending on how the question was posed—yes/no for negative questions and yea/nay for positive ones:
Will she not stay? Yes, she will.
Will he not go? No, he will not.
Will she stay?  Yea, she will.
Will he go? Nay, he will not.