I have relatives from the southern U.S., and they often use double modal verbs in their speech, like "I might could go to the market". I understand that this isn't considered standard, but it got me interested. I wondered, how would one negate this phrase?
Example: "I might could go to the market"
"I mightn't could go to the market"
"I might couldn't go to the market"
"I mightn't couldn't go to the market"
"I might could not go to the market"
Or something else? Is this phrase or any similar phrase ("might should", "might oughta") ever used in the negative? If so, how?
I would like the negated phrase to mean "I might not go to the market" in Standard English.