Well, they made a game where you can make your own microgames (D.I.Y.), and I believe an Iwata Asks revealed it was basically a dumbed down version of the inter

Well, they made a game where you can make your own microgames (D.I.Y.), and I believe an Iwata Asks revealed it was basically a dumbed down version of the internal tools they had been using, at least for the earlier DS WarioWare game (Touched.) Not sure if that quite answers your question, but I would bet it's some kind of DSL interpreted by a microgame engine.