Zander sometimes makes up perfectly fine words that seem to fit the the situation, although they are not real words according to Merriam-Webster. These are in a different -- if only subtly -- category than the "mis-speaks" mentioned in this post. It's not that he mis-hears or can't pronounce the word in question. He just uses another. Some recent examples...
Me: "Want some of my cereal?"
Zander: "I'll take a snedge of these."
While playing on one of those bouncing balls (like this one):
Zander: "If I don't hold on I might plonk back."
While eating lunch:
Zander: "Is that a new gop of ketchup?" [Referring to a new, differently-shaped bottle].