UFLI Heart Words: What They Are, Examples by Lesson, and How to Teach Them

If you teach with UFLI Foundations, you’ve probably noticed that every lesson includes a step called “Irregular Words.” These are what UFLI calls heart words — high-frequency words that contain one or more letters that don’t follow the phonics patterns students have learned so far. Words like said, the, was, and where show up constantly in reading and writing, but parts of their spelling are irregular. Students need to “learn by heart” the tricky parts while still sounding out the parts that are regular.

This page explains what UFLI heart words are, why they matter for spelling, how they differ from traditional sight words, and how to teach them effectively. It also includes a list of heart words organized by where they appear in the UFLI scope and sequence.

What is a heart word?

A heart word is a high-frequency word that contains at least one part that doesn’t follow the phonics rules a student has been taught. The “heart” in heart word refers to the specific letters that need to be “learned by heart” because they can’t be sounded out using the patterns the student knows.

Here’s the key idea: a heart word is not entirely irregular. Most of the word can be sounded out. Only one or two letters are unexpected. UFLI teaches students to identify exactly which part is “tricky” and to focus their memorization effort there, rather than treating the whole word as something to memorize by sight.

Example: the word said

• /s/ — regular, follows the rules: the letter s makes the /s/ sound
• /ɛ/ — this is the heart part: the letters ai make the short e sound, which is unexpected
• /d/ — regular: the letter d makes the /d/ sound

So in said, only the ai is the tricky part. A student who understands this has a much easier time spelling the word than one who’s trying to memorize all four letters as an arbitrary sequence.

Heart words vs. sight words: what’s the difference?

The terms “heart words” and “sight words” are often used interchangeably, but they represent different instructional approaches:

The Science of Reading research is clear: the brain doesn’t store words as visual images the way flashcard-based sight word instruction assumes. Instead, it maps sounds (phonemes) to letters (graphemes) and stores words through these connections. UFLI’s heart word approach aligns with this by maximizing the phonics connections and minimizing what has to be memorized.

This doesn’t mean sight word lists are useless — many of the same words appear on both. The difference is in how they’re taught.

How UFLI teaches heart words

Heart words are taught in Step 7 of the UFLI 8-step lesson structure. Here’s how the process works in a typical lesson:

Step 1: Introduce the word

The teacher writes the heart word on the board and reads it aloud. Students repeat it.

Step 2: Sound it out together

The teacher and students identify each sound in the word. For each sound, they determine whether the spelling is regular (follows the rules they know) or irregular (the “heart” part).

Step 3: Mark the heart

Students draw a small heart symbol under the irregular letter(s). This visual cue helps them remember exactly which part needs special attention.

For example, with the word where:

• /w/ → wh — regular (they’ve learned the wh digraph)
• /ɛ/ → e — regular
• /r/ → re — heart (the final e is silent and unexpected in this context)

Students would draw a heart under the re.

Step 4: Practice

Students practice reading and spelling the heart word multiple times across the lesson. The word appears in the connected text passage, giving students an immediate chance to read it in context.

Step 5: Cumulative review

Heart words from previous lessons are reviewed regularly. UFLI’s cumulative approach means students continue to encounter earlier heart words in sentences and passages throughout the program.

UFLI heart words by lesson

Heart words are introduced gradually throughout the UFLI Foundations program. Each lesson introduces one or two new heart words chosen because they are high-frequency words students will encounter in their reading. The words below are organized by the phase of the scope and sequence in which they are introduced.

Phase 1: The Alphabet (Lessons 1-34)

These are among the most common words in English. Students encounter them from their very first lessons.

the, a, I, is, was, his, has, of, to, do, no, so, go, we, me, he, she, be, my, by, you, your, are, or, for, her, they, have, said, says, from, come, some, one, once, what, who, where, there, were, here, very, want, put, two, could, would, should, any, many

Phase 2: Short Vowels & FLSZ (Lessons 35-41)

been, does, done, gone, give, live, their, people, because, again, against, water, other, another, brother, mother, father

Phase 3: Digraphs and Blends (Lessons 42-53)

through, thought, though, enough, friend, build, busy, buy, eye, sure, heart, heard, early, learn, earth, world, work, word, worth

Phase 4 and beyond (Lessons 54-128)

As students progress through the later phases of UFLI, fewer new heart words are introduced because students have learned enough phonics patterns that more words become fully decodable. The heart words in later lessons tend to be less common but still important:

answer, beautiful, clothes, country, couple, daughter, island, language, laugh, mountain, ocean, often, piece, straight, brought, caught, taught, weight, foreign, receipt

Note: Heart word introduction is cumulative. A word introduced as a “heart word” early in the program may become fully decodable once the student has learned later phonics patterns. For example, she is a heart word in Phase 1 (because students haven’t learned that sh makes /ʃ/ yet), but by Phase 3 the digraph sh is no longer irregular — the student now has the phonics knowledge to sound it out. UFLI uses this as a teaching moment: “Remember when she was a heart word? Now you know why sh makes that sound!”

Why heart words matter for spelling

Heart words are some of the most frequently misspelled words in early writing. Words like said, they, was, were, and because appear in nearly every sentence a student writes, so spelling them incorrectly creates a cascade of errors across their work.

The heart word approach helps with spelling in several ways:

1. Reduces the memorization burden. Instead of memorizing 4-7 letters as an arbitrary string, students only need to memorize 1-2 tricky letters. The rest is handled by phonics.
2. Builds transfer skills. When students learn to identify the heart part of one word, they develop a strategy they can apply to any new tricky word they encounter.
3. Connects spelling to reading. The same orthographic mapping process that helps students read heart words also helps them spell them. Reading and spelling reinforce each other.
4. Prevents guessing habits. Students who are taught “just memorize it” often resort to guessing when they forget. Students who know said is /s/ + heart + /d/ have a strategy even when memory fails.

For more on how phonemes and orthographic patterns work together in spelling, see our guide to phonemes vs. morphemes.

Classroom activities for teaching heart words

1. Heart Word Mapping

This is UFLI’s core heart word activity. Give students a template with boxes for each sound in the word. Students write the letter(s) for each sound, then draw a heart under the irregular part.

Example for there:

You can create heart word mapping sheets using Worksheet Creator or generate them from your UFLI-aligned word lists.

2. Heart Word Sorts

Give students a set of heart words and have them sort them by their tricky part. For example:

• Words where a says /ɛ/: said, says, any, many
• Words where o says /ʌ/: come, some, one, done, none
• Words where ou says /ʌ/: could, would, should, young, country

This activity builds pattern awareness even within “irregular” words. Students start to see that some heart words share the same kind of irregularity.

3. Look-Say-Cover-Write-Check

A classic spelling strategy that works well with heart words:

1. Look at the word, paying special attention to the heart part
2. Say each sound, pointing to the letters
3. Cover the word
4. Write it from memory
5. Check — did you get the heart part right?

4. Heart Word Dictation

During spelling practice (or as a warm-up), dictate sentences that include both regular words and heart words. Students write the sentences, then go back and circle the heart words. This builds fluency with these words in context, not just in isolation.

You can assign heart word dictation sentences as spelling tests on Spelling Test Buddy, where students hear the sentence read aloud and type their response.

5. Heart Word Snap / Memory Game

Create cards with heart words written on them (two of each). Students play a matching game where they have to read the word correctly to keep the pair. For an added challenge, have them identify the heart part when they make a match.

6. “From Heart Word to Decoded Word” Celebrations

When students learn a new phonics pattern that makes a former heart word fully decodable, celebrate the moment. Cross off the heart symbol and add a star: “You know enough now to sound out this whole word!” This is motivating for students and reinforces the idea that phonics knowledge is growing.

Common mistakes when teaching heart words

Mistake 1: Teaching heart words as whole-word memorization

The whole point of the heart word method is to use phonics first and only memorize the irregular part. If you’re showing students the word and saying “just remember it,” you’re missing the instructional power of the approach. Always sound out the regular parts first.

Mistake 2: Introducing too many at once

UFLI introduces heart words one or two per lesson for a reason. Students need repeated practice with each word before adding more. If students are struggling with heart words, slow down and spend more time reviewing before adding new ones.

Mistake 3: Skipping the heart-marking step

Drawing the heart under the tricky letters isn’t just a cute activity — it’s the instructional move that focuses students’ attention on exactly what they need to remember. Research on orthographic mapping shows that explicitly identifying the irregular part strengthens memory for that word.

Mistake 4: Not reviewing cumulatively

Heart words need ongoing review. If you teach said in week two and never revisit it, students will forget. UFLI’s connected text passages build in this review, but additional practice through spelling tests and dictation helps cement these words.

Mistake 5: Treating all heart words the same way

Some heart words are more irregular than others. A word like of (where the f says /v/) has a very small irregular part. A word like people is more unusual. Adjust your teaching emphasis accordingly — students don’t need to spend equal time on every heart word.

Heart words and students with dyslexia

Students with dyslexia often struggle particularly with irregular words because their phonological processing is already strained. The heart word method can actually be a strength for these students because:

• It reduces the cognitive load by limiting what needs to be memorized
• It provides a consistent strategy (sound out first, then identify the tricky part) rather than asking students to memorize arbitrary letter strings
• It builds on the same Orton-Gillingham-style explicit instruction that research recommends for dyslexia

For students receiving intervention, spending extra time on heart word mapping and practice can be a high-leverage activity.

Frequently asked questions

How many heart words are in UFLI Foundations?

UFLI Foundations introduces approximately 100-120 heart words across its 128 lessons. The exact number varies because some words transition from heart words to fully decodable words as students learn more phonics patterns.

Are heart words the same as Dolch words or Fry words?

There is significant overlap. Most Dolch and Fry sight words appear as heart words in UFLI. The difference is instructional: Dolch and Fry lists were designed for whole-word memorization, while UFLI’s heart word method teaches the phonics-based parts first and only asks students to memorize the irregular part.

When should I start teaching heart words?

UFLI introduces heart words from the very first lessons. Words like the, a, and I appear immediately because students need them to read even the simplest sentences. The key is to always teach them using the heart word method, not as flashcard memorization.

Can I use heart words with a non-UFLI program?

Absolutely. The heart word method works with any phonics program. The underlying principle — sound out what’s regular, identify and memorize what’s not — is grounded in orthographic mapping research and applies regardless of which curriculum you use. Programs like Orton-Gillingham use a similar concept, sometimes called “red words” or “trick words.”

How do I assess whether students know their heart words?

The simplest way is through spelling. If a student can correctly spell a heart word (including the tricky part), they’ve internalized it. You can assess this through dictation, spelling tests, or informal writing samples. Look specifically at whether students get the heart part right — if they spell sed instead of said, they know the phonics-based parts but haven’t yet memorized the irregular vowel.

Want to practice heart words alongside phonics-based spelling? Check out our UFLI word lists by lesson, explore the full UFLI scope and sequence, or read our complete guide to UFLI and spelling instruction.