It is very strange to me that people can be illiterate (as in, unable to read anything) in Mexico considering how easy the written Spanish language is (compared to e. g. English) and how prevalent is it around the globe.
They should be seeing written phrases everywhere and these should be trivial to read once they know the alphabet.
I wouldn't be surprised if the word/s the author used in Spanish for illiteracy indicated this distinction, which has then been lost in translation. Maybe.
Agreed. I learned the Russian alphabet in a day - you learn the sounds for each symbol and you're done. It took a long time to speed up, of course, and i had the background of already reading in English, but Spanish isn't Chinese or Japanese (or English for that matter).
They should be seeing written phrases everywhere and these should be trivial to read once they know the alphabet.