Story takes place during Harry Potter's fourth year.
With the second task now behind him, Harry wanted to talk things over with Sirius. Harry goes to kitchen, to try and arrange for a basket of food to take to Sirius during the Hogsmeade visit.
An elf approaches and says "Nitwit, be happy to serve. What cans Nitwit be gettings for you?"
Another elf approaches, slightly miffed, "No! Nitwit is being Hufflepuff food-elf. Blubber is being Gryffindor food-elf. Harry Potter is being in Gryffindor, so Blubber wills be seeing to Harry Potter!"
Harry has a flashback to first year and realizes the true action behind the Headmaster's words, when Dumbledore announced that he wanted to share a few words before dining, "Nitwit! Blubber! Oddment! Tweak!" Then the food had appeared. No one had understood why the Headmaster would say that... but, considering the odd names given to House-elves, perhaps he was just letting the head kitchen elves or simply the elves in charge of making the food appear, know that it was time to serve the meal. Maybe there were new elves in charge of serving the meal that year and they needed to hear the verbal command. There were four odd words... four Hogwarts Houses, so maybe with one elf in charge of the food for each House table, it would finally make some sense of the Headmaster's actions.
AN/ just something that crossed my mind that I haven't ever seen in any other story. If another author wants to use this idea, they are welcome to.