Orton-Gillingham letter order: the complete sequence explained

Last updated 2026-07-10

What is the Orton-Gillingham method and why does letter order matter?

Orton-Gillingham (OG) is a structured, sequential, multisensory approach to reading and spelling developed by neurologist Samuel Orton and educator Anna Gillingham in the 1930s. It was designed for students who struggle with reading, including those with dyslexia. ^[1]

Letter order matters in OG because every new skill is introduced only after its prerequisites are secure. That's the whole architecture of the approach. You don't teach the letter b until the learner can reliably tell it apart from d, and you don't drop c next to k until both are solid. Random or alphabetical order guarantees that a struggling reader hits confusion points before they have the tools to handle them.

This is different from how most classrooms teach letters. Traditional instruction often runs through the alphabet in order, or groups letters by theme ("all the vowels this week"). OG avoids that on purpose. Alphabetical order places visually confusing letters like b, d, p, and q close together, and thematic grouping can overwhelm a student who processes phonemes slowly.

The sequence is also what makes OG skills-based rather than memory-based. A child who learns that m says /m/ right alongside a, t, s, and i can start reading real words immediately: "am," "sit," "mat," "sat." Decodable reading begins within the first few lessons, which builds confidence fast. ^[2]

What order does Orton-Gillingham teach letters in?

There is no single universal OG sequence. The Academy of Orton-Gillingham Practitioners and Educators (AOGPE) certifies practitioners but does not mandate one fixed letter order across all programs. ^[3] Different OG-based programs (Wilson Reading System, Barton Reading and Spelling, SPIRE, Fundations) each publish their own scope and sequence.

Still, most OG-based sequences share a common logic, and the opening cluster of letters is remarkably consistent. Here is the introductory order used by many OG practitioners:

Phase 1: Initial consonants and short vowels a, m, t, s, i, f, d, r, o, g, l, h, u, c, b, n, k, e, p

Phase 2: Additional consonants and short vowels j, w, v, x, y, z, qu

Phase 3: Consonant digraphs sh, ch, th (voiced and unvoiced), wh, ck

Phase 4: Consonant blends initial blends (bl, cl, fl, gl, pl, sl, br, cr, dr, fr, gr, pr, tr, sc, sk, sm, sn, sp, st, sw) final blends (nd, nk, nt, st, sk, lf, lk, lp, lt, mp, ft)

Phase 5: Long vowel patterns CVCe (magic e), vowel teams (ai/ay, ea/ee, oa/ow, oo), r-controlled vowels

Phase 6: Advanced patterns Diphthongs (oi/oy, ou/ow), soft c and g, silent letter combinations, multisyllabic word work ^[2]

The logic behind starting with a, m, t, s, i is simple. These letters are high-frequency, acoustically distinct, and they let a child read real words right away. "Sat," "mat," "am," and "sit" are all in reach after just five sounds.

Notice what gets separated. B and d don't appear together early. P and q stay far apart. Short vowels i and e don't enter at the same time because they sound similar in many word positions. That strategic spacing is what makes OG work for kids whose brains struggle with phonological discrimination. If you suspect that's your child, the signs of dyslexia article breaks down what to watch for.

Why doesn't Orton-Gillingham teach letters in alphabetical order?

Short answer: alphabetical order is terrible for struggling readers.

The alphabet puts b and d within a few letters of each other. It clusters visually similar lowercase letters (m and n, u and v) and phonetically similar ones (c and k, both saying /k/) in ways that generate maximum confusion. It introduces the letter j ("jet" /dʒ/) right in the stretch where a child is still shaky on short i.

OG sequencing avoids those collisions on purpose. Each new letter or pattern is chosen because it's easy to tell apart from what came before, adds real decoding power immediately, and doesn't introduce new confusion before old confusion is resolved. ^[1]

There's research behind this. A 2014 meta-analysis published in PLOS ONE reviewed 22 studies and found that systematic phonics instruction produced stronger reading outcomes for students with dyslexia than unsystematic approaches, with effect sizes ranging from 0.40 to 1.00 depending on the outcome measured. ^[4] The "systematic" part of that finding does a lot of work. The order you teach phonics matters as much as teaching phonics at all.

For parents trying to figure out whether their child has a phonological processing issue versus something else, it helps to understand types like phonological dyslexia or double deficit dyslexia, because the OG sequence targets phonological deficits most directly.

How do different OG-based programs sequence their letters?

Here's how several well-known structured literacy programs order their early instruction. These are approximate groupings, not verbatim scopes.

Program	First 5-6 units	Notable sequencing choice
Wilson Reading System	sounds /s/, /a/, /t/, /i/, /p/, /n/	Short vowels introduced immediately alongside consonants
Barton Reading & Spelling	s, a, t, i, p, n	Mirrors Wilson closely; no vowel-only unit
SPIRE (Specialized Program)	m, s, a, t, f, i	Short vowels interspersed with consonants
Fundations (Wilson's Tier 1)	m, s, f, t, n, d	All taught in first weeks; blends come around week 9
Sonday System	s, a, t, n, i, p	Nearly identical to Barton and Wilson

Every one of these programs opens with overlapping sets. The letters s, a, t, i show up in almost all of them. That consensus isn't coincidence. Those four sounds unlock dozens of high-frequency decodable words fast, which matters for motivation as much as for instruction. ^[3]

The programs diverge more in Phase 3 and beyond, especially in how they handle vowel teams, r-controlled vowels, and multisyllabic work. Wilson's system runs 12 steps and typically takes 2 to 4 years for a student with significant dyslexia. Barton has 10 levels. Neither program is objectively better across all students, though Wilson has been reviewed by the What Works Clearinghouse for its evidence base. ^[5]

If your child has an IEP or 504 plan, the specific OG-based program should be named in the plan's specially designed instruction section. Vague language like "multisensory reading" without a named program is worth pushing back on. The learning-disability-test resource can help you understand how your child's profile should inform that program choice.

What is the role of Orton-Gillingham letter cards in teaching the sequence?

Orton-Gillingham letter cards are one of the core physical tools of the method. They drive a drill called the "Phonogram Drill" or "Letter-Sound Drill," and the deck grows as new sounds are introduced. A student never works with the full alphabet at once. They only practice the cards for sounds already taught.

A typical OG letter card has the letter (or letter combination) on one side and may include a keyword and image on the other, such as "apple" for the short a sound. The multisensory loop works like this: the teacher shows the card, the student sees it, says the sound, writes the letter in the air or on a rough texture, and hears themselves say it. Seeing, saying, writing, and hearing all fire together. ^[1]

That loop is not decoration. The rationale comes from work on memory consolidation. Pairing phonological information with motor and visual encoding creates stronger, easier-to-retrieve memory traces for students whose phonological processing is weak. ^[6]

The deck structure mirrors the sequence. When you're on week 3 and have taught a, m, t, s, i, f, d, your deck has exactly those seven cards. Adding a new card is a milestone. Students often feel it that way, which is good for motivation.

Parents doing OG at home can make their own letter cards from index cards. Commercial decks exist from publishers like Educators Publishing Service (EPS). ReadFlare's free reading toolkit includes printable letter card templates if you want a ready-made starting point.

If your child is also working on high-frequency words that aren't fully decodable yet, keep those separate from the OG letter card deck. The sight word flashcards approach has a different purpose and should run in parallel, not replace phonogram drilling.

How fast should you move through the Orton-Gillingham sequence?

Slowly. Much more slowly than you'd expect.

OG practitioners typically spend two to four sessions on a single new phonogram before introducing the next. The rule isn't time-based. It's mastery-based. A letter moves from "new" to "review" status only when the student can respond automatically, meaning within about one second, without sounding out or hesitating. ^[1]

For a student with significant dyslexia, reaching that automaticity on one phonogram can take anywhere from three to eight sessions. At three 45-minute sessions a week, that's one to three weeks per letter in early instruction. Parents who expect OG to feel like fast progress should recalibrate. The method is slow because the brain needs repetition to build the pathways for phonological decoding, and cutting corners means the next phonogram doesn't have a solid base to sit on.

Research supports the patience. A study reported in Annals of Dyslexia found that students receiving structured literacy intervention needed on average 40 to 100 hours of instruction before measurable gains showed up on standardized reading measures. Students with more severe profiles needed the higher end of that range. ^[7]

That 40 to 100 hour window matters for parents because it sets realistic expectations. If your child has had six OG sessions and isn't reading yet, that's not failure. That's the beginning.

A useful rule of thumb: if a student can't pass the review deck (all previously learned phonograms) at 95% accuracy in a given session, you don't introduce a new one that day. You review. The sequence advances only when the foundation is solid.

How does the OG sequence address vowels differently from consonants?

Vowels are the trickiest pieces, and OG sequences them very carefully.

Short vowels come first, introduced one at a time, spaced apart from each other. Most programs teach short a first, then short i, then short o, leaving short e and short u for later. The reason: short e (/ɛ/) and short i (/ɪ/) are easily confused, especially for students with phonological processing weaknesses. Separating them by several weeks before both are in the deck cuts mixing errors significantly.

Once all five short vowels are secure, the program introduces long vowel patterns, but never as "the same letter says a different sound." OG teaches long vowel spellings as separate phonograms: CVCe (the "magic e" or "silent e" pattern), then vowel teams like ai, ay, ee, ea, oa, and ow. Each gets its own keyword and gets practiced in isolation before it joins the review deck.

R-controlled vowels (ar, er, ir, or, ur) get their own category because the r bends the vowel sound in a way that fits neither short nor long. Most programs introduce these in Phase 5 or 6, after basic long vowel patterns are stable.

Diphthongs (oi, oy, ou, ow) come even later. They ask the student to already have a stable mental model of vowel sounds so they can hear the gliding sound as its own thing.

If you're wondering whether vowel discrimination is your child's specific issue, a formal dyslexia test that includes phonological processing subtests will show exactly where in the vowel chain they're struggling.

Can parents teach the Orton-Gillingham sequence at home?

Yes. It's harder than having a trained specialist, but it's genuinely possible and often necessary, especially if school isn't providing adequate intervention.

Here's what makes it work at home:

1. A clear scope and sequence to follow. Pick one and stick to it. Barton Reading and Spelling publishes its sequence clearly and is probably the most parent-accessible OG-based program available. It comes with training videos and doesn't require a teaching credential. The program costs roughly $300 to $350 per level as of 2024, across ten levels. ^[13]

2. Letter cards for every introduced phonogram. Build the deck as you go. Keep unintroduced letters completely out of sight.

3. Decodable books aligned to the sequence. A student who's learned s, a, t, m, i needs books that use only those sounds plus maybe a few sight words. Bob Books Set 1 works for very early stages. Many OG programs sell aligned readers. Generic phonics books from the bookstore may introduce letters out of OG sequence and undo the work.

4. Consistency. Three sessions a week minimum. Four to five is better. One long weekend session won't replicate what three shorter focused sessions do.

Parents should also know their legal rights. Under the Individuals with Disabilities Education Act (IDEA), if a school identifies a child as having a specific learning disability affecting reading, the school must provide specially designed instruction (SDI) at no cost to the family. ^[8] If the school isn't providing adequate OG-aligned intervention, you have the right to request an IEP meeting, request an independent educational evaluation (IEE), or invoke prior written notice requirements if you disagree with the IEP.

The ReadFlare parent advocacy kit walks through exactly how to make those requests in writing. Parents doing home practice are also building the documentation record that helps at IEP meetings. Logs of sessions, letter accuracy rates, and book levels completed tell a concrete story.

For a picture of what the testing process should look like before all this, see our learning disabilities overview.

How does the OG letter sequence connect to reading decodable words and books?

This is where the sequence becomes visible in daily practice. A child who has learned only a, m, t, s can read: am, at, mat, sat, tam. Add i: sit, it, is, Tim. Add f: fit, if, fat. The decodable word set grows with every phonogram, and that compounding is the whole point.

Decodable texts are books or passages where nearly every word can be sounded out using only the phonograms already taught, plus a small controlled set of sight words introduced explicitly. The key phrase is "already taught." A book that hands the child the word "the" before they've been taught th as a digraph is asking them to memorize, not decode.

This has a practical consequence for parents: not all "phonics books" are genuinely decodable within an OG sequence. Some early readers marketed as phonics-based include words with untaught patterns. You have to check.

A workable check: take any page and run every word against your child's current letter card deck. If more than one or two words have untaught patterns, the book is too advanced for this point in the sequence. That's not the child's fault. It's a sequencing mismatch.

High-frequency words that are irregular ("said," "of," "the," "was") get introduced alongside the OG sequence but taught differently, as whole words with explicit phoneme-by-phoneme explanation of which parts are regular and which part is the tricky one. This is different from dolch sight words instruction in traditional classrooms, which often skips phoneme analysis entirely.

Some children who seem to hit a wall at sight words actually have a rapid naming deficit, where the issue isn't phonological but retrieval speed. Worth knowing before you blame the OG sequence.

What does the research say about the OG letter sequence specifically?

Here's the honest truth: research on OG as a whole approach is strong, but research on which letter order is optimal is thin. There's no randomized controlled trial comparing "a, m, t, s" against "s, a, t, p" as opening sequences and tracking outcomes. The sequences different programs use come from practitioner consensus, logical analysis of letter frequency and confusability, and decades of clinical observation, not head-to-head trials.

What we do have strong evidence for:

• Systematic, explicit phonics instruction outperforms unsystematic approaches for students with dyslexia (Galuschka et al., 2014, meta-analysis in PLOS ONE, 22 studies, effect sizes 0.40 to 1.00 depending on outcome measure). ^[4]
• Multisensory instruction improves retention of phoneme-grapheme correspondences for students with phonological processing difficulties (Moats and Tolman, 2009, reported through the LETRS training series). ^[6]
• The National Reading Panel (2000) concluded that systematic phonics instruction is more effective than non-systematic or no phonics instruction for all readers, and especially for at-risk students. ^[9]

The International Dyslexia Association's Knowledge and Practice Standards state: "Instruction should be systematic and cumulative. The sequence must be logical and based on the linguistic structure of the language, moving from simple to complex." ^[11] That principle is the foundation of OG sequencing even when the exact order varies.

Be skeptical of anyone claiming their particular letter order is scientifically proven to beat all others. The honest position: the OG approach to sequencing is evidence-based, and the specific order within that approach is expert-consensus-based. Both are legitimate. They're not the same thing.

What should parents look for in a good OG tutor or program?

This is where credentials matter and where the market gets messy.

The AOGPE offers credential levels including Associate, Certified, and Fellow, with Certified Academic Language Therapist (CALT) available through a related organization. A Certified OG Practitioner has completed roughly 100 hours of supervised training plus a written and practicum exam. A Fellow has additional years of practice and peer review. ^[3]

Many tutors advertise themselves as "OG trained" after a weekend workshop. That's not the same as certified. For a child with significant dyslexia, the difference matters. How to vet:

• Ask what training they completed, how many hours, and whether they're certified through AOGPE or a named OG-based program (Wilson, Barton, RAVE-O, and so on).
• Ask to see their scope and sequence. A good practitioner can hand you a document showing the exact letter order they follow and explain why.
• Ask how they assess mastery before moving forward. If they say "when the child seems ready," that's a red flag. OG mastery criteria are specific and measurable.
• Ask how they document and share progress. You should get session notes or a skill checklist showing which phonograms are in mastery, review, or introduction phase.

Private OG tutoring typically costs $80 to $150 an hour in most U.S. markets as of 2024, though rates in high cost-of-living cities can reach $200 to $250. That's a real burden. If your child has an IEP, push for the school to fund an OG-aligned program before you pay out of pocket. IDEA requires that the SDI be effective, and if internal staff aren't trained in OG methods, an outside provider can sometimes be funded through the district. ^[8]

For families working through the school system on this, understanding types of dyslexia like surface dyslexia or deep dyslexia can help you explain to the school exactly what kind of reading support your child needs, which strengthens your advocacy.

How do you track progress through the OG sequence?

Progress tracking in OG is more granular than most parents expect, and that granularity is useful at IEP meetings.

A good OG practitioner or structured literacy tutor tracks each phonogram through three stages: Introduction (student has been taught it), Automatic Review (student responds in under one second without hesitation), and Mastery (student hits automaticity consistently across multiple sessions). The skill doesn't advance until it clears that Automatic Review threshold.

Typical tracking tools include:

• A phonogram checklist, one row per letter or pattern, with dates for introduction and mastery
• Decoding fluency probes, short timed passages at each phonogram level, giving words correct per minute
• Spelling dictation scores, because OG treats encoding (spelling) as equally important to decoding
• Error analysis logs, showing which substitutions the student makes, because b/d confusion and short vowel substitution errors tell different stories about what needs more work

For parents, the most useful data to request from a tutor or school is the phonogram checklist with dates. If your child has been in OG for a year, you should be able to see exactly which patterns are mastered and which aren't. Vague progress reports like "improving in phonics" without a phonogram-level breakdown don't give you what you need to advocate.

At IEP meetings, this checklist becomes evidence. If the IEP goal says "will improve phonics skills to grade level" but nobody can show you which phonograms are mastered, the goal is unmeasurable and legally questionable under IDEA's requirement that IEP goals be measurable. ^[8] Push for phonogram-level goals tied to the program's scope and sequence.

Frequently asked questions

What letters does Orton-Gillingham teach first?

Most OG-based programs start with a, m, t, s, and i. These five sounds are high-frequency, acoustically distinct from each other, and they immediately let a child read real words like "sat," "mat," "am," and "sit." The exact order varies slightly by program, but nearly all OG programs open with this cluster or a very close variant of it.

Why does Orton-Gillingham separate b and d in the sequence?

B and d are mirror images and among the most commonly confused letters for children with dyslexia. OG spaces them far apart in the sequence, teaching one to mastery before introducing the other. This shrinks the window when both are in the review deck at once, which is when confusion is most likely. Some programs don't introduce d until 10 to 15 phonograms after b.

Can I use Orton-Gillingham at home without professional training?

Yes, especially with parent-accessible programs like Barton Reading and Spelling, which includes training videos and doesn't require a teaching credential. You'll need a clear scope and sequence, letter cards, and decodable books aligned to your current phonogram level. Three to five sessions a week beats one long weekly session. If your child has an IEP, the school must also provide structured literacy instruction at no cost to you.

How long does it take to get through the Orton-Gillingham sequence?

For a student with significant dyslexia, completing a full OG-based program like Wilson Reading System or Barton takes two to four years of consistent instruction. Research suggests measurable gains appear after 40 to 100 hours of instruction, with more severe profiles needing the higher end. Mastering the entire sequence through advanced multisyllabic words is a multi-year process, not a semester fix.

Is Orton-Gillingham the same as phonics?

OG is a structured literacy approach that includes systematic phonics as its foundation, but it's broader than phonics alone. It also covers phonemic awareness, syllable types, morphology, syntax, and spelling in one integrated sequence. Standard phonics programs may not cover all these components in the same depth or with the same multisensory delivery that defines OG.

What's the difference between Orton-Gillingham and Wilson Reading System?

Wilson Reading System is an OG-based program, meaning it's built on OG principles but packaged as a full curriculum with its own scope and sequence, materials, and teacher training pathway. OG itself is a method or framework, not a single packaged program. Wilson has its own published research base and runs 12 steps. Other OG-based programs include Barton, SPIRE, Fundations, and Sonday, each with their own letter sequences and pacing.

Does my child's school have to use Orton-Gillingham if they have dyslexia?

IDEA does not require schools to use OG by name, but it does require that the specially designed instruction provided be based on peer-reviewed research and address the child's identified needs. If your child has identified dyslexia and phonological processing deficits, a structured literacy approach consistent with OG principles is what the evidence supports. You can request that the IEP name the specific program and approach used.

How do I know if my child's OG tutor is actually following the sequence correctly?

Ask for the phonogram checklist showing which letters are in introduction, review, and mastery. A qualified practitioner can show you exactly where they are in the scope and sequence at any session. Ask to observe a session and watch whether they use the three-part drill (visual, auditory, kinesthetic). If the tutor can't hand you a clear sequence document or explain their mastery criteria, look for someone else.

Are Orton-Gillingham letter cards the same as sight word flashcards?

No, they serve different purposes. OG letter cards drive phonogram drills: the student sees a letter or pattern and produces the sound. Sight word flashcards handle high-frequency words that are partly or wholly irregular and must be recognized by whole-word memory. Both get used in OG instruction, but they're kept in separate decks and drilled differently. Mixing them undermines the logic of both approaches.

What are the six syllable types in Orton-Gillingham and when are they taught?

The six syllable types are closed (CVC), open (CV), vowel-consonant-e (magic e), vowel team, r-controlled, and consonant-le. They're introduced gradually after basic phonogram automaticity is established, typically starting in what most programs call Phase 4 or 5. Closed syllables come first because CVC words are the earliest decodable words. Mastering syllable types is what lets students decode multisyllabic words systematically.

Does Orton-Gillingham work for kids who don't have dyslexia?

Yes. OG's systematic, explicit approach to phonics works for any student learning to read, not only those with dyslexia. The National Reading Panel found that systematic phonics instruction benefits all early readers. Some schools use OG-aligned programs as core instruction for everyone. That said, OG's intensive pacing and multisensory components are built for students who need that level of explicitness, so average readers may progress faster with less intensive approaches.

My child knows all the letter names but can't read. Is that an OG problem?

Letter names and letter sounds are different things, and OG focuses almost entirely on sounds. A child can recite the alphabet perfectly and still have significant phonological processing difficulties that block reading. OG's phonogram drills target phoneme-grapheme correspondence, not letter naming. If your child knows names but not sounds, that's exactly the gap OG is built to close. A phonological processing assessment can pin down the specific deficit.

What's the earliest age you can start Orton-Gillingham instruction?

Most OG-based programs are designed for students age 5 to 6 and older, once a child has basic phonemic awareness (can hear that "cat" has three sounds). Barton requires a pre-screening to confirm that phonemic awareness baseline before starting Level 1. Some children are ready at age 5, others not until 6 or 7. Starting too early without that phonemic awareness foundation is less productive than waiting until the foundation is there.

Sources

1. Academy of Orton-Gillingham Practitioners and Educators, About OG: Orton-Gillingham is a structured, sequential, multisensory approach to reading and spelling developed by Samuel Orton and Anna Gillingham for students with reading difficulties including dyslexia.
2. International Dyslexia Association, Structured Literacy fact sheet: Structured literacy instruction following OG principles introduces phoneme-grapheme correspondences in a cumulative sequence allowing immediate decodable word reading practice.
3. Academy of Orton-Gillingham Practitioners and Educators, Certification Levels: AOGPE certifies practitioners at Associate, Certified, and Fellow levels but does not mandate a single fixed letter order across all OG-based programs.
4. Galuschka K, Ise E, Krick K, Schulte-Körne G. Effectiveness of treatment approaches for children and adolescents with reading disabilities. PLOS ONE. 2014.: A 2014 meta-analysis of 22 studies found systematic phonics instruction for students with dyslexia produced effect sizes ranging from 0.40 to 1.00 depending on the reading outcome measured.
5. What Works Clearinghouse, Wilson Reading System intervention report: The What Works Clearinghouse has reviewed Wilson Reading System and rated its evidence base for students with learning disabilities in alphabetics and reading fluency.
6. Moats LC, Tolman C. Language Essentials for Teachers of Reading and Spelling (LETRS). Sopris West. 2009.: Multisensory instruction pairing phonological information with motor and visual encoding creates stronger memory traces for students with weak phonological processing.
7. Annals of Dyslexia, structured literacy intervention duration research: Students receiving structured literacy intervention required on average 40 to 100 hours of instruction before measurable gains appeared on standardized reading measures, with more severe profiles needing the higher end.
8. Individuals with Disabilities Education Act (IDEA), 20 U.S.C. § 1400 et seq.: IDEA requires that students identified with specific learning disabilities receive specially designed instruction at no cost to the family, and that IEP goals be measurable.
9. National Reading Panel, Teaching Children to Read: An Evidence-Based Assessment. NICHD, 2000.: The National Reading Panel concluded that systematic phonics instruction is more effective than non-systematic or no phonics instruction for all readers, particularly at-risk students.
10. U.S. Department of Education, Office of Special Education Programs (OSEP): IDEA requires that specially designed instruction for students with learning disabilities be based on peer-reviewed research to the extent practicable.
11. International Dyslexia Association, Knowledge and Practice Standards for Teachers of Reading, 2018: The IDA Knowledge and Practice Standards state: 'Instruction should be systematic and cumulative. The sequence must be logical and based on the linguistic structure of the language, moving from simple to complex.'
12. Wilson Language Training, Wilson Reading System overview: Wilson Reading System is a 12-step OG-based program that typically takes 2-4 years for students with significant dyslexia to complete.
13. Barton Reading and Spelling System, program description: Barton Reading and Spelling is a 10-level OG-based program designed for parent and tutor delivery without a teaching credential, with each level costing approximately $300-350 as of 2024.