Abby= Abbygirl, Abbydurl, Babygirl, Missy (usually when she's in trouble), Pretty girl, and most recently Miss Fatty Fat Fat (when she tries to eat Nate's food)
Nathan= Nate, Nateboy, Nater, Natey-Natan, Boy-boy, Boo boo boy, Mamas-boy Natan
Collective= AbbyNathan (as one word) and for some reason "Where you at?" seems to work. Go figure........