No we haven't, but i read the Glenn Doman books (on baby/toddlers reading) using flashcards. It does work but it's basically graphics recognition. I've taught my currently 2 years old son chinese characters that way (using chinese flashcards); although i've been lazy and do so only occasionally, he can recognize quite a few chinese characters. In terms of English, i prefer to do it even more loosely and let him learn to read using Phonics when he's older (as in upper Kindergarten). Learning is life long and it's best to plan out when to teach what at an age appropriate level.