Are sight words and decodable words opposites?

No. Most words on a typical school sight-word list are fully decodable with first-grade phonics — about 70–80% of the Dolch 220, depending on which analysis you use. A sight word, in the modern reading-science sense, is simply any word a child recognizes instantly, without sounding it out. Decodable words become sight words through reading practice. The genuinely irregular ones (was, of, the, said, who) are a small group, sometimes called heart words, and those are the ones worth a memorization routine.

Should I make flashcards for sight words?

Generally no, and never for the whole list. For decodable sight words (most of them), the child should encounter them inside real sentences in a decodable book. For genuinely irregular heart words (about 30–50 across all of K–2), flashcards can help only if the routine identifies which letters are regular and which one is the "heart" exception. A stack of 200 opaque flashcards is the old balanced-literacy approach and has been shown to hold back kids with reading difficulties.

What are heart words?

Heart words are high-frequency words that have at least one letter that doesn't follow regular phonics rules — was, of, said, one, the, who, because. The teaching routine identifies the regular letters, marks the irregular one (often with a heart or circle), and asks the child to learn just that fragment by heart. The rest of the word is decoded normally. This is the current best practice from structured-literacy programs aligned with Orton-Gillingham.

How many "true" sight words does a child need to memorize?

Fewer than parents are told. About 30 to 50 genuinely irregular words across all of K–2, taught using the heart-word routine. Compared to the traditional 220-word Dolch list, that is a fraction of the workload. The remaining 170-or-so Dolch words should be learned through phonics instruction and oral reading practice, not whole-word memorization.

My school still sends home a long sight-word list. What should I do?

Don't drill the whole list as flashcards. Go through it once and sort each word: decodable (most of them) or heart word (a small minority). Practice the decodable ones inside sentences from a real book — that builds the same automatic recognition the list is trying to produce, but through phonics. Use the heart-word routine for the genuinely irregular few. Fifteen minutes of oral reading from a decodable book beats twenty minutes of flashcards every time.

Sight Words vs. Decodable Words: What's the Difference?

By Readigo editorial team · 2026-05-23 · 11 min read

Short answer

A decodable word is any word your child can sound out using the phonics patterns they've been taught (cat, ship, bike). A sight word is a word your child recognizes instantly, without sounding it out. The confusion: most words become sight words once a child can decode them automatically. The small list parents really need to memorize is irregular high-frequency words like was or of, sometimes called "heart words." Everything else, including most of the classic Dolch list, should be taught with phonics, not as flashcards.

What is a decodable word

A decodable word is one whose spelling matches a phonics pattern your child has already learned. If they know short vowels and the consonants m, s, t, p, n, c, h, d, g, then cat, mat, sat, hid, dog, cog are all decodable for them. The child looks at the letters, applies the sound-spelling rules, blends the sounds, and the word comes out. Decodability is relative to the child, not absolute. Light is decodable for a kid who has learned the igh trigraph. It isn't decodable for one who hasn't. This is why structured-literacy programs publish a scope and sequence: a chart that shows which sounds get introduced in which order, so the books and the practice line up. Around 84% of English words are fully decodable once a reader knows the common patterns, according to the analysis used by the International Dyslexia Association. Another 10–14% are mostly decodable with one tricky letter (the l in talk, the s sounding like z in was). Only a tiny fraction are genuinely irregular. The whole point of phonics instruction is to walk your child through the patterns so that this huge pool of words becomes accessible to them. For a deeper guide to what makes a book decodable and how to use them, see decodable books explained. For a level-by-level book list, see the decodable books list by level.

What is a sight word (and the two definitions parents confuse)

Here is where most parents get tangled, because the term sight word is used in two very different ways. Definition A — the modern, reading-science definition. A sight word is any word a reader recognizes instantly, without conscious decoding. After enough practice reading dog in books, your child stops sounding it out and just knows it on sight. Dog is now a sight word for that child. So is because. So is elephant. So is your child's own name. Becoming an automatic, fluent reader is, in this view, the process of converting decodable words into sight words. Cognitive scientist Linnea Ehri calls this orthographic mapping, and her research has shaped most modern phonics curricula. Definition B — the older, classroom-tradition definition. A sight word is a high-frequency word a child is taught to memorize as a whole, often from a list like the Dolch list (220 words, compiled by Edward Dolch in 1936) or the Fry list (1,000 words, Edward Fry, 1980). The idea was that these words show up so often that drilling them as wholes saves time. This definition is the one that drives flashcards, sight-word checklists, and "first 100 sight words" wall charts in classrooms. The modern definition is the right one. The old one is responsible for a lot of confused parenting. When a kindergarten teacher sends home a list of "sight words to memorize this week," most of those words (and, can, get, had, not, run) are fully decodable with basic phonics. Memorizing them as wholes works at first, then collapses once the list gets long. There are only so many shapes a brain can hold.

The Dolch list is mostly decodable

Take the most famous list in American reading education, Edward Dolch's 220 words. Researchers like Devin Kearns and others have shown that around 70–80% of the Dolch list is fully decodable with first-grade phonics (basic vowels, consonants, common digraphs). Another 10–15% is partly decodable, where one letter behaves oddly (was, put, who). Only a small minority is genuinely irregular. The practical implication: when the teacher sends home twenty "sight words" this week, your job is not to make flashcards for all twenty. Your job is to find the three or four that are actually irregular and treat those as heart words. The rest should be practiced through reading actual decodable text, not memorization. This is the heart of the disagreement between balanced literacy (the older approach that taught sight words as wholes and used predictable books) and structured literacy (the modern, Science-of-Reading approach that teaches phonics first and reserves whole-word memorization for genuinely irregular words). For more on that fight, see phonics vs. whole language.

Heart words: the modern compromise

The term heart words is the current best practice for handling the small set of genuinely irregular high-frequency words. It comes out of structured-literacy classrooms, especially programs aligned with Orton-Gillingham principles. A heart word is a word with at least one letter that doesn't follow regular phonics. Was, of, the, said, one, who, because are classic examples. The s in was sounds like z. The o in of sounds like uh. The teacher tells the child: most of this word follows the rules, but this letter you have to learn "by heart." The routine looks like this. Write the word. Have the child identify the regular letters (the ones whose sounds match the rules). Circle, underline, or draw a heart over the irregular letter. Say: the w and the s are regular. The a is the heart part. We just have to remember it. Then practice reading the word in real sentences, not on a flashcard. This is dramatically more effective than the old approach because it builds on phonics rather than fighting it. The child still uses sound-spelling knowledge for the regular parts, and only memorizes the genuinely irregular bit. Linnea Ehri's orthographic-mapping research shows this is how the brain actually stores words, by mapping sounds to letters, with the irregular bits tagged as exceptions. A reasonable beginning-reader heart-word list is small: about 30 to 50 truly irregular words across all of K–2. Compare that to the 220 Dolch words traditionally memorized. That is the size of the actual workload, once you stop forcing decodable words into the memorize-as-whole pile.

How to teach each one

The teaching method should match the word type. Mixing them up is the most common parenting mistake. Decodable words are taught through explicit phonics instruction plus oral practice. Show the pattern. Say the sounds. Blend them. Read words with that pattern in lists, then in sentences, then in books. Repeat with new patterns. The point is to build a sound-spelling map your child can apply to any word that follows the rule, not just the ones on this week's list. Heart words are taught with a phonics-anchored memorization routine. Identify the regular letters first. Mark the irregular bit. Practice reading the word in real text. Only resort to flashcards for the truly irregular fragment. Never present the whole word as opaque. A few things not to do. - Hand your kindergartener a stack of 50 flashcards and call them "sight words." Most of those words are decodable. Teach the phonics instead. - Skip the decodable-book stage in favor of memorizing a long sight-word list. It works for the first 100 words and then hits a wall. The brain runs out of room. - Confuse can your child read it without sounding it out (the goal) with should you teach it that way (often the wrong method). Speed comes from practice, not from skipping the decoding step. For the broader picture of how all five reading pillars fit together at home, see the pillar guide on how to teach a child to read.

What about your school's sight-word checklist?

Most U.S. schools still send home sight-word checklists. They aren't going away. Here is the pragmatic way to handle them without undoing the phonics work. Decode the list first. For each word, ask: can my child sound this out with the phonics they've been taught? If yes, that word is decodable. Treat it as a practice word, not a memorization word. Read it inside a sentence in a real book and move on. If no, mark it as a heart word and use the heart-word routine. Don't drill the whole list nightly, either. Twenty minutes of flashcards every evening is the worst use of your child's reading time. Fifteen minutes of oral reading from a decodable book is better, because it builds phonics, fluency, and the kind of automatic recognition that turns words into sight words organically. And treat the school's checklist as a diagnostic tool, not a study plan. If your child can read all 50 words from the Dolch primer set without sounding them out, fine, move on to longer text. If they stumble, look at which words they stumble on. If it's the regular ones (can, get, had), they need more phonics work. If it's the genuinely irregular ones (was, said, of), they need the heart-word routine. Both are fixable, but the fix is different. For parents who want a practical checklist by grade, the grade 1 sight words checklist, grade 2 checklist, and grade 3 checklist on this site mark which words are decodable and which are heart words, so you can split practice the right way.

Why the difference matters for struggling readers

For most kids, getting the sight-word-vs-decodable distinction a bit wrong won't ruin reading. They'll figure it out. For two groups, it matters a lot. Kids with dyslexia or other reading difficulties. Their phonics knowledge is fragile and slow to build. Forcing them to memorize 220 "sight words" as wholes is the worst possible approach, because it asks them to rely on the part of reading they're weakest at (visual word memory) instead of the part that can grow with structured instruction (phonics). The Orton-Gillingham approach, the gold standard for dyslexia intervention, is explicit about this: phonics first, heart words narrowly defined, and never as a substitute for decoding. Kids who got the wrong methodology in K–1. A child who was taught to look at the picture and guess in kindergarten arrives in second grade with a habit of avoiding the letters. They have a small bank of memorized sight words, no real decoding, and they stall the moment the books get harder. The fix is to back up and teach the phonics they skipped, even at age 7 or 8 — sometimes called structured literacy intervention. This is one of the patterns laid out in the Mississippi Department of Education literacy reforms, which credit the shift away from sight-word memorization as a major driver of the state's reading-score gains. If your child is in either group, the distinction in this article is not academic. It is the difference between the method that works for them and the one that has held kids like them back for decades.

Where reading practice tools fit

Once your child has the phonics-vs-heart-words framework in place, the next bottleneck is volume of oral reading with feedback. The traditional answer is a parent listening attentively, every day, for 15 minutes. The realistic answer is that most parents can't quite hit that consistency. A reading practice app earns its place when it does the listening work the parent can't always do, without shortcutting the phonics. The text inside the app should be sequenced by phonics pattern (not random sight words). It should give feedback at the word level when the child misreads. It should show parents which patterns are sticking and which need more practice. Readigo, the practice app behind this site, was built around that brief for ages 6–12. The reading library is structured around phonics progression. The mascot Igo listens as the child reads aloud, scores accuracy and pace word by word, and surfaces the specific stumbles each week. Sight words are practiced inside real sentences, not as flashcards. Heart words are tagged in the program so the child gets the right routine for the right word type. None of this replaces the parent or the decodable books on the shelf. It just makes the daily practice happen on the days when life gets in the way. If you want the methodology in more detail, read the research foundation Readigo is built on or see how it works for parents day-to-day.