the grammar one learned, unconsciously, while growing up speaking the language. There's a Funniest Home Videos clip where Mom is behind the camera, filming her chocolate-smeared toddler, and she says things like, "You didn't eat no candy, did you?", and "Are you sure you didn't eat no candy?" (To every question, of course, the kid says no.) And I think, "Lady, aren't you embarrassed to be heard on national television talking like that?" This is a pretty old clip; the kid's probably in grammar school right now, talking the same way as his mom.