Even when I was a child, with no or very little education in English under my belt, the chapter "E/A-Anweisungen" in my trusty GW-BASIC manual confused me to no end. I'm pretty sure that I would have grasped the meaning of "IO".
Where those terms still rule unchallenged is in MS Excel formulas. All the function names are translated. When you are a native speaker but used to programming vocabulary, Excel expressions read like hieroglyphics: you can easily identify most of the symbols, but the semantics remain unknown.