Young children who are learning to speak can also learn to read. That's a given (see 1, 2, & 3), but we cannot provide a detailed explanation of how to do it here. Instead, we will offer some preliminary considerations, an overview of the process, and some ways to find more help for those so inclined.
The first and most important consideration is to stress how important it is for the parents or other persons involved NOT to feel that they are actually "teaching," or that a schedule should be followed, or that the child WILL learn to read whether he or she wants to or not. Those notions will make the process unpleasant for the child and likely lead to failure. The learning experience should be fun for the child (and the parent), not a series of pass/fail tests. It should be conducted like a game, with laughter, smiles, and joking around. The parents should be thinking of empowering the child, NOT enabling him or her to get into a better school eventually or amaze the neighbors. Small children love to be empowered--any parent knows the delight in a child's voice when he or she reads "Stop" on a stop sign, or "Kentucy Fried Chicken" while driving by a fast food establishment. That's the kind of delight children should have when reading word cards.
So, assuming that the parents are the sort who enjoy the company of their young children at least periodically, then we can move to word cards. There has always been a controversy about the virtues of the "whole word" method of reading instruction versus "phonics." This controversy thrives in elementary schools, with six and seven year olds and older, and will not be reviewed here. Instead, we'll describe a demonstration we used with college students.
The students were instructed to look at a screen where a word would appear for perhaps one quarter of a second. The first word was "terrific." Every student, as soon as the word disappeared, instantly said it out loud: "terrific!" Then they were told to wait for another word. This word was "syzygy." After it disappeared, the classroom buzzed with the sound of students saying "sssss," "zzzz," "sizzy," and so forth, all laughing. When the word was put back on the screen, some actually figured out how to pronounce it. Here's the point: when they read the word "terrific," they were actually reading--getting the meaning from the symbols instantly, without thinking about it. That's what we do when we read. But when they came to an unfamiliar word, they had to proceed a letter or syllable at a time, maybe getting the meaning in the process or maybe not. That's NOT reading--that's decoding. That's phonics. We all use phonics when we're stuck, but that's not an efficient way to extract meaning from printed language. The whole word method is how we read, whole words or whole phrases at a glance, or even, in proficient readers, whole sentences. And that's how little children best start to read.
We've known parents who use card stock, or cardboard, to make word cards, word cards with single words in large, easy to see letters, words that hold special meaning for their toddlers, like their own names, their words for their parents and siblings, pets, and so forth. (See the photo above.) Children of two or three who are beginning to talk two and three words at a time are ready to try this. It's important not to go too fast. Start with one card the first couple of days, and read it for the child. If the child eventually reads it before it is read for him or her, there should be a general celebration followed by the second card, which is also read for the child. When he or she can differentiate between them, bring out the third card. If the child is distracted or not interested, then postpone any further sessions for several months. You will know when the child is ready to continue when you see their delight.
The children we are familiar with soon get the hang of this process, and even request (or demand) other words be written for them: favorite foods, people, animals, all sorts of unpredictable things. Always stop before the child wants to; don't overload him or her with new words. One or two a day is the limit. The size of the word doesn't matter. "Great grandmother" is easily read. At first, children will recognize words by their first letter, or the presence of double letters, or maybe their overall length, or even by a splash of grape juice on one corner of the card. That doesn't matter.
Eventually, they will be able to read 40 or 50 words, and confusion will set in. This is good! One child had a devil of a time differentiating hand, head, and hair. She first learned hair, because "it has a dot." That left hand and head, which required some extra study. Eventually, she figured out which was which on her own, with the help of her mother's hints. This is exactly how children learn to speak as well--by practicing, studying, and trying again. It's crucial that they not be criticized for their miscues. It's a game. It should be fun.
At some point, perhaps between 50 and 100 word cards, their eyes will be getting accustomed to the letters, and the size of the letters can be reduced to one inch. Parents can create fun activities: flash card games, words laid out on the floor (to accustom the child to left-to-right reading), nonsense sentences, or even sentences of the child's creation. Children can even dictate entire stories which can be written out on card stock for reading later, on their own. One child loved a game where she was given a card that said "There is a pretzel under your pillow," or "Find the cookie on your bed." She learned to take the card along on her search, to consult in case she forgot a crucial detail. Thus she learned, by age four, that writing could lead to food!
As it happened, Ana and Matt Méndez used word cards with their children, for both English and Spanish, only being careful to conduct a single session in one language. They were delighted when three year old Julio, for example, saw the word "pato" and said "duck," or saw "table" and said "mesa!" He understood the meaning of the word instantly, but spoke it in whatever language came to him first. That is real reading: getting the meaning from print instantly. It was not a mistake! (When they got to the sentence stage, this no longer happened.) Both children were soon able to read themselves to sleep in two languages. Unfortunately, however, the Méndez family was unfamiliar with the different alphabets of the other languages their nannies used, so they weren't able to use word cards for them
Several of the parents mentioned in the examples above used a simple, inexpensive book as a guide: How To Teach Your Baby to Read, by Glen Doman. It's still in print (with a co-author), along with myriad other titles promising to give children superior brains. We can't recommend any but the basic book. Parents can easily create their own word cards without paying for commercially prepared materials. We are intrigued, however, by Teach Your Baby Math, also by Glen Doman. If it seems that learning mathematics is too difficult for a young child, we disagree. Basic math is simpler than language: it's completely logical and there are no exceptions! If we had a two or three year old handy, we would try this ourselves. (We wonder if some of the unfavorable reviews for those books might be from demanding parents who set goals and had expectations for their children. We don't know...but we wonder.)
In any case, teaching small children to read in two languages is a good way to help them become bilingual. Each case will depend on many variables. Clearly, it's best if at least one parent is bilingual, the more fluent the better. A child who is even partially bilingual at an early age will have an advantage later on should the opportunity present. As long as the parent-child sessions are no pressure, fun occasions, they will be time well spent, for both parents and their children.