Orthographic mapping of irregular words: how tricky words get stored

What is orthographic mapping?

Orthographic mapping is how a word goes from something a student sounds out to something the student simply knows. The student hears the sounds in a word, sees the letters, and links the two. After a few successful readings, that link is strong enough that the word is recognized at a glance, without any conscious decoding.

Linnea Ehri described this process over several decades of studies. Her central point is that the connection between sounds and letters is the glue. A reader doesn't store a picture of "ship". The reader stores sh linked to /sh/, i linked to /i/, and p linked to /p/, in that order, and retrieves the whole bundle at once.

Can irregular words be mapped at all?

Yes. This surprises some teachers, who were trained to think irregular words must be memorized as wholes. In fact, almost every irregular word is mostly regular. "Have" has three sounds, and two are spelled exactly as you'd expect. "Friend" has five sounds, and four of them are spelled the normal way.

The student maps the regular parts in the usual way. The irregular part gets mapped too, as an unusual link that the brain flags: in this word, ie spells /e/. Holding one odd fact like that is far easier than holding a whole visual pattern, and it scales to hundreds of words.

What does a student need before mapping works?

Two skills have to be in place. The first is phonemic awareness, which means the student can hear and separate each sound in a spoken word. The second is letter-sound knowledge, which means the student knows which letters usually spell which sounds.

Without the first skill, there's nothing to attach the letters to. Without the second, every letter looks arbitrary, so every word seems irregular. This is why phonemic awareness and phonics come first in a well-planned sequence, and heart words are built on top of them rather than taught in their place.

How do you teach so mapping happens?

Mapping is something the student's brain does, and you can't do it for them. You can set it up, though. Every step of a good heart word routine pushes the student to connect a sound to a letter, and each connection makes the next one easier.

• Start with the spoken word, so the sounds are clear before any print appears.
• Have the student segment the word aloud before seeing it written.
• Show the letters one sound at a time, moving from left to right.
• Name the odd part explicitly, so the student doesn't have to discover it alone.
• Have the student spell the word from memory, which forces attention to every letter.
• Revisit the word in text within a day, and again several times over the next week.

Spelling is the strongest of these steps. A student who can spell "could" from memory has almost certainly mapped it. A student who can only pick it out from a set of choices may not have, even if they seem to know it.

How many exposures does mapping take?

Fewer than drill-based methods assume, as long as each exposure involves decoding. In studies of typical readers, a handful of correct readings is often enough to store a regular word. Irregular words usually need more, and students with weak phonemic awareness need many more than their classmates.

So don't count exposures. Count successes. A word read correctly in a sentence, without help, five days in a row is very likely stored. A word seen 50 times on a card but never actually decoded may not be stored at all.

Why do some students map words and others don't?

Most of the difference comes from phonemic skill. Students who can quickly break a word into sounds and blend them back together map words with very little teaching. Students who struggle with that, including many students with dyslexia, need explicit support for each new word.

That doesn't mean they need a different method. They need the same method with more of the steps made visible, more spelling practice, and more review spaced across days. Short, frequent practice beats long sessions for these students every time.

Does mapping help with spelling too?

It does, and the link runs both ways. Mapping a word stores its spelling along with its pronunciation. Students who learn heart words with spelling practice spell them better in their own writing, because they remember which letters stand for which sounds.

Spelling errors are also a useful window for you. When a student writes "sed" for "said", they've mapped the sounds but not the unusual spelling. Point to the heart part and have them correct it themselves, rather than just copying the word again.

What does this mean for older students?

Older students who never mapped common words often read them slowly or swap them for similar words. The fix is the same routine, adjusted for age. Explain the idea of mapping directly, since many older students find it a relief to learn that the words aren't random.

Work through their problem words a few at a time, and add spelling in every session. Most older students make quick gains once the regular parts are pointed out.