Ni-noh?

In case I haven't mentioned it to you in person, the girls do have at least one secret twin word, a word they use that only exists in their personal lexicon.  I'm sure there are others bubbling up but I have only noticed this one clear word,  "Ni-noh".  They say it when they want to trade toys.  I know if I hear it from another room that I will look in and find them swapping plates or push-toys or spoons or whatever.  I will be on the lookout for other secret words.