You all know that Dex has a great linguistic ability, but now he's proving Chomsky right (at least the U-shaped curve bit about language development). This evening at dinner, while I was reading "Bus Route to Boston," Declan corrected (he's taken to correcting me when I misread one of his favorite stories) 'cannoli' to 'cannolis' in the sentence "then, of course, we ordered four cannoli." Try explaining the fact that when English speakers adopt words from a different language, we maintain the original plural conjugation to a three-year old!
He did correctly note shortly thereafter that Moma Olga "did have something different like Spanish or something." (she, in fact, speaks Russian)