The iPhone iteration of 5th Cell's magical word puzzle game gains voice control on the 4S, integrating Siri's voice recognition technology in Scribblenauts: Remix to make you say things like "Giant Flying Kielbasa" in mixed company.
I always found the real joy of playing Scribblenauts in its various incarnations was doing completely horrible things on the DS or iPhone without anyone around you being aware of the evil in your heart. I suppose then it's good that I do not own an iPhone 4S and therefore won't be tempted to shout "Rotting Baby Bunnies!" while waiting in line at the DMV.
Well, no more tempted than I normally am.
The Scribblenauts Remix Scribble Speak feature should be available in the iPhone 4S version of the game as you speak.