More Southern Grammar: Double Modals

Whoa!  Sounds fancy, doesn’t it?  It’s hard to believe that something many people consider “bad grammar” has such a fancy name.
So what the hell am I talking about?  From Wikipedia:  “A modal verb (also modalmodal auxiliary verbmodal auxiliary) is a type of auxiliary verb that is used to indicate modality – that is, likelihood, ability, permission, and obligation.  Examples include the English verbs canmust and should.”
So it follows that a double modal is using two of them at once–like a double negative, except they don’t cancel each other out (neither do double negatives, not really–English isn’t math, after all!).
When I studied double modals in linguistics classes there were several examples listed, but the only one I use or hear used is “might could.”  Example:  “Mommy, can we go to the store?” “Well, we might could go later.” Here’s another:  “Can you tell me how to get to the interstate?” “You can take Dutchtown Road, or you might could take Bob Gray.”
It’s hard for me to explain why Southerners say this or exactly what it means.  It’s been suggested that it arises from our innate politeness, especially in the second example where we wouldn’t want to TELL a stranger what to do, but would rather offer a gentle suggestion.
Another thing, unlike “Y’all,” which as I explained in an earlier post is considered a high prestige usage and is quickly picked up by immigrants to the South, the use of double modals is viewed unfavorably and is rarely assimilated.   Speakers seem themselves to sense this–analysts have had a difficult time getting examples when people knew they were being recorded, and would often not hear double modals until they pretended the interview was over and asked for directions to their next stop!  It’s not something that I would typically use in writing, not even in something informal like a letter or a status update, whereas I use y’all in that context all the time.  It’s not something I’d say in a job interview either.
And although I know when to say it–I wouldn’t even have to think twice about it–all I can tell you is that there is a subtle difference in meaning between double modals and single modals.  In the first example, it’s somewhat more than might and less than could.  If any of my Southern readers think you might could explain it better, have at it in the comments!