Key takeaways
- A heart word is a word with an irregular part: a letter or two that does not follow the usual sound-spelling pattern.
- Children sound out the regular letters and learn only the irregular part by heart.
- In most irregular words, only one or two letters do not conform to their usual sound correspondence, so most irregular words are at least partially decodable.
- The method only works when the regular parts are decodable. If a child cannot blend the regular sounds, check phonemic awareness and letter-sound knowledge first.
- Teach the irregular part, keep the rest decodable, and meet the word again in the next text.
Short answer: A heart word is a word with an irregular part: a letter or two that does not follow the usual sound-spelling pattern. Children sound out the regular letters and learn the irregular part by heart. The method works because children store words by connecting each letter to a sound, a process called orthographic mapping, not by memorizing the shape of the whole word.
Why do heart words matter in K–3 reading?
Some of the first words a child meets are the least cooperative. The, was, said and of appear in early texts constantly, and none of them sounds the way it looks.
The What Works Clearinghouse practice guide from the U.S. Department of Education tells teachers to teach irregular high-frequency words so students can recognize them efficiently. The open question is how. The guide's own examples of practice include flashcards, word walls and small-group work.
Heart words are one answer, and the research on how children store words backs it. Children do not photograph a word. They attach each sound to a letter, and that attachment is what makes the word instantly readable later.
At a glance: heart words, irregular words, high-frequency words and sight words
These four terms overlap, and people often use them interchangeably. They are not the same.
| Term | What it means | What decides it | Examples |
|---|---|---|---|
| Heart word | The irregular part of a word, learned by heart. Teachers also use the term for a word taught this way. | The spelling of the word | The e in the; the ai in said (our illustration) |
| Irregular word | A word with exceptions to the typical sound-spelling patterns | The spelling of the word | was, of, said |
| High-frequency word | A word that appears very often in printed text. It can be regular or irregular. | How often the word is printed | the and was (irregular); in and and (regular) |
| Sight word | A word a reader recognizes instantly, without conscious effort | The reader | Any word a child has mastered |
The last row surprises people. Linnea Ehri, whose research on word learning is the foundation for most of this, writes that people used to regard sight words as limited to high-frequency or irregularly spelled words, but "all words when practiced become read from memory by sight." Sight word status describes a reader's relationship with a word. Heart word describes the spelling of the word.
What exactly is a heart word?
Take said as an illustration. The s and the d behave. The ai does not: it says /e/. A child can sound out two of the three units. Only the ai has to be learned by heart.
That ratio is typical. The University of Florida Literacy Institute (UFLI), which publishes a set of printable heart word cards, says that in most irregular words, only one or two letters do not conform to their usual sound correspondence. Most irregular words are at least partially decodable.
UFLI sorts irregular words two ways:
- Permanently irregular words include a sound-spelling correspondence that is unique to that word or to a few words. Said is one.
- Temporarily irregular words only look irregular because the child has not been taught every correspondence in them yet. As our own illustration, a word with igh looks irregular until the igh pattern is taught, and is regular afterward.
UFLI gives a worked example. In Lesson 1, the is taught as an irregular word, and both th and e get hearts because students have not yet learned the th digraph. Once th is taught, only the e is permanently irregular, so only the e keeps its heart. The same word carries a smaller heart load as the child learns more phonics.
How do children learn to read words, according to research?
When a child reads a word, say its pronunciation and match its sounds to its letters, the spelling becomes bonded to the pronunciation and the meaning in memory. Ehri calls this orthographic mapping and says that to build sight words in memory, orthographic mapping is required. UFLI and the Massachusetts Department of Elementary and Secondary Education describe the same mechanism in their guidance.
Two skills have to be in place first. Ehri states that orthographic mapping is enabled by phonemic awareness and grapheme-phoneme knowledge. In practice the child must be able to hear and blend the separate sounds in a spoken word and must know the main letter-sound correspondences. That is why phonics instruction and heart word instruction belong together.
The timeline matters too. Joan Sedita's summary, published by Massachusetts DESE, notes that some orthographic mapping can begin earlier, but most children start applying it in second and third grade.
Should children memorize irregular words by sight?
UFLI says no: students should not be taught to memorize irregular words by sight. Instruction should help them map the letters to the sounds, even when the correspondence is unusual.
The federal practice guide, published in 2016, reads differently. For irregular words it says to teach them holistically, as whole words rather than as combinations of sound units. It pairs that advice with flashcards, word walls and small-group practice.
The two positions disagree. The heart word method sits with the orthographic mapping research. It asks a child to hold one or two surprising letters in memory instead of a whole word. Teachers can keep word walls and flashcards for practice. The change is in how the word is introduced.
None of the sources behind this article compares heart word instruction head-to-head with whole-word drilling, so a claim of a measured advantage would go beyond the evidence. The case rests on how word learning works.
How do you teach a heart word? A step-by-step routine
Steps 1 to 6 follow UFLI's published directions. Step 7 is an addition. Keep each word short.
- Cover the symbols and say the word. Show the word without hearts or sound boxes. Say it aloud. Students repeat it.
- Find the irregular part together. Match each sound in the word to its letters. Stop at the part that does not match the usual pattern. Name it plainly: "In said, the ai says /e/" (our illustration, not UFLI's wording).
- Point out useful chunks. UFLI's example is the -ould in could, would and should. One memorized chunk covers three words.
- Say the sounds with the teacher. Students say each sound, including the irregular one, then blend the sounds into the word.
- Say the sounds alone. Students repeat the sounds and the blend without the teacher.
- Write it while saying each sound. Students write the word as they say each sound, then repeat the writing several more times. Vary it: write it big, small, fast, slow.
- Revisit it in connected text. Keep the word in the next few decodable sentences so the child meets it again soon.
Step 7 is not in UFLI's card directions. It applies Ehri's finding that rereading a word a few times moves it into memory.
Which words are heart words?
The answer depends on the phonics sequence your school uses. Some words stay irregular for good. Others only look irregular until the child has been taught every correspondence in them.
| Type | What it means | Example words |
|---|---|---|
| Permanently irregular | Has a sound-spelling correspondence that stays unusual | the, said, was, of, to, do, are, from, were, what, your, could, would, should, there, where, who, one, once, two |
| Temporarily irregular | Looks irregular until the pattern is taught, then becomes regular | the (before th), she (before sh), night (before igh), play (before ay) |
The permanent list comes from UFLI's printable cards. The federal practice guide's examples of irregular high-frequency words overlap it: the, was, from, of, there, said and friend, plus have and want. The temporary examples are illustrations; your own scope and sequence decides which words fall there.
How many times does a child need to practice a word?
A small number, for children who already map well. The Massachusetts DESE summary reports, citing Sedita, who cites Kilpatrick (2015), who in turn cites Reitsma (1983), that typically developing readers from grade 2 on who have orthographic mapping skills need to see and read a printed word one to four times before it is permanently stored. That figure has passed through those secondary citations, so treat it as an estimate for that group.
It does not describe kindergarten, first grade or struggling readers. The same summary notes that many students with word-reading difficulties do not develop orthographic mapping without intervention that builds phonemic awareness and phonics. More flashcards will not fix that. The summary points to intervention that builds phonemic awareness and phonics.
The practice guide also gives a sensible limit on volume. Teach a small number of words at a time, and choose words students have just met in text.
What if a child cannot sound out the regular letters?
Then the heart word has nothing to attach to. The method only works when the regular parts are decodable.
If a child cannot blend /s/ and /d/ around the ai in said, the problem is upstream, in phonemic awareness or letter-sound knowledge. Adding hearts will not fix it. The practice guide rates the evidence as strong for two recommendations: developing awareness of the sounds in speech, and teaching students to decode, analyze word parts, and write and recognize words. Those are ratings of the recommendations as a whole. For irregular words, the guide's own advice is to teach them holistically, so the rating is not a verdict on heart word instruction.
Check the foundation first. If a child can segment and blend the sounds in a word but stumbles on the irregular letters, a heart word is the right tool.
Where do heart words fit in a reading program?
Heart words serve word recognition. They do not replace phonemic awareness, phonics, fluency, vocabulary or comprehension. For the full picture, read the 5 components of the science of reading and what the science of reading is.
Teach the irregular part, keep the rest decodable, and meet the word again in the next text.
If your school is looking at teacher training in the science of reading, talk to Eight Strands Literacy.
Frequently asked questions
What is a heart word?
A heart word is a word, or the part of a word, that does not follow the usual sound-spelling pattern. Children sound out the regular letters and learn the irregular part by heart. As an illustration, take the word said: the s and d are regular, and the ai is the part to remember.
What are some examples of heart words?
Common examples include the, said, was, of, to, do, are, from, were, what, could, would, should, there, where, one, once and two. Which letters carry the heart depends on what the child has already been taught, because a word can be temporarily irregular.
Are heart words the same as sight words?
No. A sight word is any word a reader recognizes instantly, whether it is regular or irregular. A heart word describes a spelling feature, the irregular part of a word. A child can turn a heart word into a sight word, but so can any other word with enough practice.
Why not just memorize irregular words by sight?
Whole-word memorization asks a child to hold every letter of the word in memory with no connection to sound. The heart word method asks for only the one or two letters that break the pattern and uses the sounds for the rest. UFLI advises against teaching irregular words as whole-word memorization. The federal practice guide takes a more holistic view.
Do heart words replace phonics?
No. Heart word instruction depends on phonics. Orthographic mapping requires phonemic awareness and knowledge of grapheme-phoneme correspondences, so a child who cannot sound out the regular letters cannot map the word. Build phonics skills first, then teach heart words alongside the phonics sequence so each new pattern turns more irregular words into regular ones.
How many heart words should I teach at once?
Keep the number small. The What Works Clearinghouse practice guide advises selecting a few high-frequency words that students have just met in text, and limiting how many hard-to-decode words you introduce at a time. Add new words as the earlier ones become automatic.
Keep reading
- The 5 Components of Reading (Science of Reading)
- What Is the Science of Reading? A Guide for Leaders
- Scarborough's Reading Rope Explained
- The Simple View of Reading
- What Is Structured Literacy?
Sources
- University of Florida Literacy Institute (2022). Printable Cards for Irregular "Heart" Words.
- University of Florida Literacy Institute (2024). UFLI Foundations Pocket Reference.
- Ehri, L. C. (2014). Orthographic mapping in the acquisition of sight word reading, spelling memory, and vocabulary learning. Scientific Studies of Reading, 18(1), 5-21.
- U.S. Department of Education, Institute of Education Sciences, What Works Clearinghouse (2016). Foundational Skills to Support Reading for Understanding in Kindergarten Through 3rd Grade.
- Massachusetts Department of Elementary and Secondary Education. Orthographic Mapping, adapted from Joan Sedita, Literacy Lines (2020).
Krista L. Johnson, Ph.D.
Chief Executive Officer
Krista L. Johnson, Ph.D., is the Chief Executive Officer of Eight Strands Literacy. She holds a Ph.D. in Communication Sciences and Disorders from Northwestern University, with research in auditory neuroscience, and graduate training in specific learning disabilities. She leads the organization's work helping schools put the science of reading into practice.
