How Phonics Helps Your Child To Read

If you're like most parents, you already understand that phonics helps children learn to read. But you can do more to help your child if you have a really firm understanding of how and why phonics works. There are two things you can do to gain a deeper understanding of phonics. One is to study the comparative research to see if phonics instruction actually outperforms other teaching practices (for more on this see our phonics research page). The other is to develop a logical explanation of how and why phonics works. That is the purpose of this page.

In order to understand how and why phonics works, we need to know some facts about words and about how children acquire vocabulary. First, it is important to realize that individual word recognition is absolutely essential for reading(1,2,3,4,5,6). A person who cannot recognize the great majority of words on a page certainly cannot be reasonably expected to read or understand the text. (This would seem to be self-evident, but amazingly there are people who argue against this idea.) We assume from this point onward that you agree that individual word recognition is essential to reading.

How Many Words?

A typical English college dictionary contains about 200,000 entries(7). "Entries" are not necessarily words, though. An entry is simply something that is highlighted and defined. An entry might be a common word, but it might also be a letter, a prefix or suffix, a proper name, a combination of other words, or any of a number of other things. If we eliminate the entries that are not complete common words, we find that there are about 100,000 common root words in English(7,8). By "root" we mean a word that is not formed from other words by adding prefixes or suffixes.

For example, we can consider the word cook to be a root word because it is not formed from other words. We could form other words from cook by adding prefixes like pre, under, and over or by adding suffixes like ed and ing, to form words like precook, undercooked, and so on. However we would not regard these as root words because they are all formed from cook. If we consider all the possible words that can be formed by using all the valid combinations of prefixes and suffixes, and if we add in all the popular proper names, we can conservatively estimate that a person will encounter over half a million distinct words during a lifetime of reading(8).

Types Of Vocabulary

Now let's distinguish between two types of vocabulary:

  1. Verbal vocuabulary is the set of spoken words that a person can recognize and understand.
  2. Written vocabulary is the set of written words that a person can recognize and understand.

Children acquire verbal vocabulary automatically during the course of talking and listening to conversation, and they do so at an astonishing rate. Various research studies conducted since the 1940s have come up with different estimates of the size of a typical child's verbal vocabulary upon entry to school, but all seem to agree that this number is somewhere between 10,000 and 24,000 words(6,9). After entry to school, children acquire additional vocabulary at an incredible rate of between 3,000 and 5,000 words per year. That's between 8 and 13 words per day, seven days per week, every week of the year.

There seems to be no analogous capability when it comes to print, however. We might expect this since verbal communication is undoubtedly as old as the human race, whereas alphabetic languages were invented only about 4,000 years ago and came into widespread use only after the invention of the printing press about 550 years ago. As much as it is likely that natural selection has enhanced our verbal skills over the relatively long period of human development, it is equally unlikely that it has played any part in selecting out individuals with inherent reading skills during the relatively brief period in which printed text has been available to the masses.

Verbal vocabulary grows automatically because words are heard in the context of real-life situations where the meanings of the words are fairly obvious. Whether through interaction in conversations or through passive listening, there is generally a tremendous amount of context which can be derived from people's actions and expressions. Conversation is a particularly powerful teacher, since the child is actively constructing speech and receiving feedback from adults and peers.

There is nothing that corresponds to a conversation in reading. Two people cannot "read to each other" in the same way that they can talk to each other. A child does not generally construct his own sentences when reading, and even if he does there is no opportunity for immediate feedback. If reading aloud, the only opportunity for feedback occurs if an adult is following along with the story; however this is a contrived situation for which some adult must intentionally make time. When reading, the only context is in the pictures (which if present contain relatively little information) and in other printed words. Since the other printed words are likely to be no more decipherable than the words the child is trying to learn, they tend to be of little help. Finally, even under the best of circumstances, a child's exposure to books is far more limited than his or her exposure to conversation.

Two Ways To Acquire Written Vocabulary

There are only two ways to acquire written vocabulary: either you use phonics to convert written words into the spoken words that you already know, or you must memorize the meaning of each and every written word as if written English were an entirely new language.

There is little available scientific research to indicate how many written words a child can memorize in a year. However we can get some clues from the many reading texts produced during the past several decades that have attempted to teach reading without the use of phonics. Students using these texts acquire their written vocabulary by memorizing lists of words. A survey of such texts reveals that they expect children to memorize anywhere from 400 to 600 words per year. Since the authors of these texts were presumably interested in having children memorize as many words per year as possible, then we may presume that through experience they learned to limit themselves to at most 600 words (due to children's inability to memorize more).

In contrast, a phonics based reading program does not rely on word memorization. Instead it is based on the idea that children can "sound out" words using various rules about how written letters and letter groups represent sounds. Children then reconstruct the verbal words by making or imagining those sounds. When reading age-appropriate text, children will tend to already know the verbal equivalents of the words they are reading. Quite simply, they comprehend written text by translating it into spoken words whose meanings they already know.

There are over 400 different phonetic rules that govern how letters can be used to represent sounds in the English language, but about 220 of these are either archaic or used so infrequently that there is no point in learning them. This leaves about 180 rules that are commonly regarded as being both modern and frequently used enough to be worth teaching. Children who have been taught these rules thoroughly can decode about 85% of all English words perfectly. Another 12% of the language consists of words that contain one sound that does not follow the phonetic rules (almost always a vowel), but these words are also decodable. The reason is that readers can still produce the sounds of the other letters in the word, thereby reducing the number of possibilities for pronunciation to a very small number. For example, the word "some" is non-phonetic in its vowel sound; however there is really only one pronunciation that would produce the one spoken word that would fit the context in which this word might appear. Using a combination of phonics and context, a student can decode this additional 12% of the language (so long as the words appear in the context of a meaningful sentence) without any need for guessing.

Thus English is about 97% decodable. This has some very important implications for students who have learned phonics comprehensively:

  1. Their recognition and understanding of printed words does not require memorization of those words. At any given time, they can automatically read a large fraction (97%) of the verbal words they already know.
  2. Their acquisition of new printed words does not require any practice or even a conscious effort. They acquire written words "for free" at only slightly less than the incredible rate at which they automatically acquire verbal words.
  3. In later years, the word acquisition process works in reverse. If a student encountering unfamiliar written words can figure out the meaning of those words from the context in which they are used, then he can automatically add those words to his verbal vocabulary since he knows their pronunciations. A student who encounters a list of the chemical elements, for example, can add all of those elements' names to his verbal vocabulary without having to ask someone else to say their names.

Phonics vs. No Phonics

The primary advantage of phonics becomes immediately clear when we look at the differences in the rates of written word acquisition for phonics vs. non-phonics students. In the chart below, the area below the highest line represents an aggressive example of a child's verbal acquisition, starting with 20,000 words at age six and increasing by 5,000 words per year. The line immediately below that represents the written words acquired by the phonics student pretty much automatically, at a rate of 97% of the verbal acquisition rate after phonics training is completed at age 8. The bottom sloping line represents the rate at which we can expect a child to acquire written words without phonics, by memorizing them at a rate of 600 per year.

As unfortunate as the student without phonics might seem, this graph is probably optimistic for several reasons. First, it assumes that the student is consistently memorizing 600 words per year without fail and without forgetting. However it is unlikely that any student actually continues such memorization after the first five or six years during which word memorization is taught explicitly.

Second, the verbal acquisition rate for non-phonics students is probably considerably lower than the level shown here. This is because in the later years most vocabulary acquisition in phonics-trained students comes from reading. This verbal acquisition can occur only because the student can translate new written words into spoken words instantly, and thus almost every new learned written word also becomes a new learned spoken word. But to the student without phonics training, written words cannot be converted into spoken words. If such a student is going to learn the spoken version of a newly learned written word, he must do so separately within the context of some conversation, and even then he may not necessarily connect the two. Thus the non-phonics student not only suffers from vastly reduced written word acquisition, but also from substantially depressed verbal acquisition in later years.

A third thing that is not obvious from the graph is the dichotomy in the mind of the non-phonics student between spoken and written words. In early years, the non-phonics student learns written words through drills in which a teacher associates the memorized written words with their sounds. However as the student ages this type of instruction is eventually abandoned, after which he starts developing two separate sets of vocabulary that are not necessarily connected - a verbal one and a written one. If the student learns a new spoken word through conversation, he is not likely to recognize it in print. If he learns a new written word through reading, he is not likely to recognize it when spoken. As time goes by and the student is expected to develop vocabulary more and more from written text, the student's ability to discuss what he's learned from reading diminishes, because he doesn't know how to say the written words he's memorized. In contrast, the phonics student automatically learns the verbal equivalent of almost every new learned written word and vice-versa.

The predicament of the non-phonics student becomes worse still when we consider the non-"root" words, i.e. words that are formed by adding suffixes and prefixes to other words. To the non-phonics reader, every such word is a different pattern that needs to be memorized separately. For example, cook and uncooked have quite different appearances when we simply look at them as wholes. The phonics-trained student has extensive practice in recognizing suffixes and prefixes, and can immediately dismantle "uncooked" into its three major constituents. To the non-phonics reader, uncooked is simply another pattern to be memorized. So the non-phonics reader must memorize not merely 100,000 root words, but rather half a million or more variations on those words(8).

An Illustration

Let's imagine two fifth graders who are reading some text containing the word astronomy. Let's further suppose that both students have heard this word before and know what it means, but that neither of them has ever seen it in print. Finally, let's assume that one student was trained in phonics and the other wasn't.

Within a few seconds the phonics student will decode astronomy, perhaps saying the word or perhaps just imagining the sound. Since he knows the verbal word already, he can immediately apply the same meaning to the written word. He has no need to make a permanent visual association between the written word and its meaning, because he can always rely indirectly on the verbal meaning that he's already acquired.

The non-phonics student might try to guess the meaning of astronomy from context. His ability to do this will depend upon how familiar he is with the other words and concepts in the passage. The more difficulty he has reading the rest of the passage, the less likely that he will deduce the proper meaning of the word. Even if he is successful, performing the deduction will interrupt the train of thought that he was developing while reading the sentence. To reestablish it, he may have to reread the sentence.

In any event, deducing the meaning purely from context is unreliable(6). If the non-phonics student wants to be certain about the meaning then he has only two courses of action. If a more knowledgeable person is present, he can ask that person to look at the word and explain it. If no such person is present, then he must look the word up in a dictionary. If he looks it up, he may encounter a definition like, "the study of extraterrestrial objects". If he has already memorized the appearance of the word extraterrestrial and all the other words in the definition, then he will understand the meaning. If not, he must then look up the unknown words from the definition. When he is done with lookups, he will finally understand the meaning of the printed word, but may still not be sure that it is the same as the spoken word astronomy. He might guess from the meaning that the two are the same, but of course there could be several words that have that meaning or a similar meaning. Only when someone else expressly says the word while pointing to the printed version can he be sure which verbal word is the right one.

What About Context?

It might seem that we have been overly pessimistic about the results of avoiding phonics because we haven't considered the possibility that the non-phonics student could use context to figure out the meanings of unknown words. Unfortunately there's a catch: in order to establish a context, the reader must understand most of the other words in the passage without using context. So in order to use context, a reader must already be skilled in the use of other methods. Further, the quality of the reader's context (and hence his deduction) will depend upon his level of skill in using those other methods. But the more skilled he is in using other methods, the less likely he is to have needed to use context in the first place. So using context is a bit like getting a bank loan: the people who need it the most are the least likely to get it, and the people who need it the least are the most likely to get it and use it successfully.

Since phonics students can decode about 85% of the language reliably without using context, they have the highest possibility of developing a reliable context from which to work. For the 12% of the language containing only one phonetically abnormal sound (requiring some deduction on the part of the student), the choices of possible spoken words can usually be counted on the fingers of one hand, and so phonics students have a small number of possibilities from which to choose. Let's consider a sentence like:

I had a lot of trouble today.

Upon seeing the word trouble, a phonetically trained child can immediately produce the relatively few spoken words that the written word might represent. By using context to select from those relatively few choices, he is very likely to succeed (in this example he'll have to choose from treble, tribal, trouble, and tribble if he's a Star Trek fan). The child without phonics training, however, must choose from among all the imaginable words that could fit the context. Even if we stick to very common words that start with "t" (many non-phonics reading texts recommend teaching a child only to sound out the initial letter of a word), the list of possibilities could include tacos, taffy, tailwind, talent, tarts, tasks, tea, teasing, time, traffic, training, traction, transfusions, transmissions, trash, trauma, travel, treatment, treats, tremors, trials, tribulations, trifles, trigonometry, triumphs, trivia, trouble, trousers, trucks, tuna, turkey, turnips, turnover, tutoring, and typing. Even more onerous than choosing from a potentially long list of words that might fit the context is developing the list itself. A reader could spend minutes thinking of all the words that might fit, and of course he could never be sure that he had thought of every one. Now of course there may be enough context in the preceding sentences to allow the reader to figure out the proper word, even from a long list of possibilities. But if those sentences were read using the same combination of weak reading strategies that we are using here, then the reader probably knows little more about the preceding sentences than he does about the current one.

Context is at best a secondary reading strategy that relies heavily on the concurrent use of a strong primary word recognition method, and so it is least useful to the children who are using weak primary strategies such as whole word memorization. The use of context also depends upon how well the reader's previous experiences relate to the topic being read, and so it is least useful to children who have had the fewest opportunities for intellectual growth. For these reasons, context should be regarded only as an additional option for students who are already experiencing success in reading due to their use of strong word recognition methods (i.e. phonics).

What About Sight Vocabulary?

One frequent criticism of phonics is that students never develop a "sight vocabulary" (a set of words that are recognized instantly on sight), and so they must spend their lives laboriously sounding out every word rather than simply memorizing and instantly recognizing words as wholes. Ironically, the truth is precisely the opposite.

The phonics student deciphers unknown words relatively easily. After a few seconds of "sounding", the child most often recognizes the word as being a spoken one that he or she already knows. The non-phonics student must either ask someone to say the word or even worse must go through the laborious task of looking it up in a dictionary, in which case he may be further stymied by being unable to read unfamiliar words in the dictionary definition. During early reading most written words are unknown to the reader, and for older readers many of the significant words (i.e. information-laden nouns and verbs as opposed to the more common articles, conjunctions, pronouns and such) are still unknown. Because of the large amount of work involved in performing dictionary lookups, non-phonics students quickly learn to avoid text containing unknown words. In contrast, phonics students have no such disincentive, and so they tend to feel free to read just about anything.

The result is that phonics students end up reading much more and enjoying it more because reading doesn't involve much work. While reading, they are also inadvertently memorizing frequently-seen words, and so are developing a phenomenal sight vocabulary. They use real books to perform sight memorization pleasurably and unconsciously, adding new sight words almost effortlessly, whereas non-phonics students must resort to dictionaries, word lists, and teachers (who may not be present when needed). While classroom experience tells us that students seem limited to approximately the 600 words that are presented explicitly each year in non-phonics reading programs, phonics students seem to suffer from no such limitation, as evidenced by the fact that as adults they read many thousands of common words without sounding them out.

Thus both phonics and non-phonics students participate in whole word memorization. Non-phonics students do it at a very slow rate, apparently limited only by the tediousness of memorizing the words from lists, whereas phonics students memorize thousands of words per year. As adults, phonics students are therefore significantly faster and smoother readers, ironically because they have developed far larger sight vocabularies than students who attempted to do so directly.

How Much Drill?

Another frequent criticism of phonics is that it requires drill. This is true, but the question we must ask is this: how much drill would be required of a student who does not learn phonics, in order to achieve the same result as the phonics student? Since it is not really possible for the non-phonics student to achieve the same result as a phonics-trained student, we can do the next best thing by comparing the normal achievements of phonics students against the best possible efforts of non-phonics students:

Goal or Attribute Phonics Student Non-Phonics Student
Age at which student might be expected to have developed a 100,000 word written vocabulary 23 173
Number of discrete facts to be learned through drill 181 phonetic rules in two years plus an initial set of about 600 sight words 600 hundred sight words per year, indefinitely
Automatic written word acquisition rate 2910 to 4850 per year after the age of eight 0 per year indefinitely
Verbal/written vocabulary correspondence 97% automatically 100% when trained explicitly through drill; 0% otherwise

Clearly, a person who despises drill should advocate the use of phonics.


It is difficult to overstate the importance of providing a child with comprehensive training in phonics. Taking chances with this most essential information-age skill is probably the most expensive mistake that a parent can make. Further, the more trouble your child has reading, the more important it is that he or she be provided with the chance to learn reading through phonics.

Many young children who have had no phonics training appear to read reasonably well. This is possible because books for very young children tend to contain so few words that they can be read easily with even a very small sight vocabulary. This is unfortunate, because the child's passable early reading performance disguises the underlying problem that he will face later in life, which is an inability to read age-appropriate materials due to a lack of written vocabulary.

In the field of reading psychology there is a term called the "Matthew Effect", which derives its name from the Biblical parable which states that the poor will get poorer and the rich will get richer. Nowhere does this notion apply more powerfully than in the area of childhood reading instruction.

Children who get an early "leg up" through phonics start reading earlier, find reading easier, and enjoy reading more. Their habit of reading causes them to develop a large sight vocabulary, which in turn facilitates even more reading. Successful reading exposes them to a greater number of concepts, allowing them to comprehend a wider variety of subjects. This comprehension in turn allows them to read about a yet wider range of related subjects. Finally, the synergy between their verbal and written vocabularies causes both to increase at a much higher rate, further facilitating reading.

Children without phonics occupy a spectrum. The "naturals" who figure out phonics for themselves will do just fine. To the degree that children fail to understand the phonetic rules, they will encounter reading difficulties. Reading will be inhibited by the tedium of needing to continually memorize word lists and look words up every time they want to read about a wider range of subjects. This disinclination to read will limit their reading practice and hence also limit their development of sight vocabulary. The absence of sight vocabulary causes them to resort to more unpleasant lookups and memorization. The lack of new subject matter causes them to know less and consequently to be able to comprehend less during reading, even when they can decipher the words. As children get older and the number of unfamiliar words in age-appropriate text grows ever higher, the disinclination to read becomes ever greater.

Phonics is not merely one of a number of reading strategies from which we may feel free to pick and choose. It is essential because it provides students with capabilities that are simply not available through any other means. It is the only reading method that does all (or indeed any) of the following:

The structure of our alphabetic system allows us to construct an arbitrarily large number of words - far too many to be internalized directly through word memorization. And so our alphabetic system also requires us to equip our children to use that system in the manner intended by its designers - as an encoding of spoken sounds.


1. Why Children Succeed or Fail at Reading, publication #0073 of the National Institute of Child and Human Development (NICHD). (order hard copy on line at NICHD Publications or call 800-370-2943).

2. Overview of Reading and Literacy Initiatives, publication #0101 of the National Institute of Child and Human Development (NICHD). (order hard copy on line at NICHD Publications or call 800-370-2943).

3. The Alphabetic Principle and Learning to Read, research program report number #0053, available at no charge from the NICHD (order hard copy on line at NICHD Publications or call 800-370-2943).

4. Getting Ready to Read: Learning How Print Maps to Speech, research program report #0024, available at no charge from the NICHD (order hard copy on line at NICHD Publications or call 800-370-2943).

5. Learning To Read: The Great Debate, Jeanne S. Chall (1967, 1983, 1993).

6. Beginning to Read: Thinking and Learning About Print, Marilyn J. Adams (1990).

7. Any typical college dictionary (available at your local library or book store) contains about 200,000 entries and documents the existence of well over 100,000 distinct English words, and will document over 400 distinct phonetic rules from both archaic and modern English.

8. The number of words in printed school English, William E. Nagy and Richard C. Anderson, University of Illinois as Urbana-Champaign, July 1982, ERIC Document 218-596. This study concludes that a student will encounter about 88,500 distinct English word families and about 609,500 graphically distinct words during the course of a typical K-12 education.

9. Why Johnny Still Can't Read, Rudolf Flesch (1981).

10. NICHD Research Supports the America Reads Challenge, G. Ried Lyon et. al. Among the many conclusions of 30 years of large scale, long-term NICHD research on thousands of students is that "the most reliable indicator of difficulties in comprehending what is read is the ability to read words quickly and accurately."