Dysorthography represents a major challenge in the field of speech therapy, affecting between 3 and 5% of school-aged children. This specific disorder of spelling acquisition, of neurobiological origin, is characterized by persistent difficulties in correctly spelling words, despite appropriate teaching and the absence of intellectual disability.

Often associated with dyslexia, dysorthography can also manifest in isolation, creating a particular profile where reading may be preserved while writing remains deficient. This dissociation highlights the importance of a differentiated assessment and targeted therapeutic interventions.

This comprehensive guide is aimed at speech therapists and rehabilitation professionals, offering a scientifically based approach to understanding, assessing, and treating dysorthography. We will explore the underlying neuropsychological mechanisms, validated assessment tools, and the most effective intervention strategies.

The goal is to provide practitioners with the theoretical knowledge and practical tools necessary to effectively support dysorthographic patients, taking into account individual specificities and current scientific recommendations.

The COCO THINKS and COCO MOVES applications from DYNSEO offer innovative digital solutions to complement traditional rehabilitation, allowing for regular and motivating training of spelling skills.

3-5%
of children affected by dysorthography
80%
of cases associated with dyslexia
3
main types of dysorthography
85%
improvement with appropriate care

1. 📋 Definition and Neuropsychological Bases of Dysorthography

Dysorthography is defined as a specific and lasting disorder of spelling acquisition, occurring in children of normal intelligence, without sensory deficits or psychiatric disorders, and who have received appropriate teaching. This disorder falls within the framework of specific written language disorders (SWLD) and is part of the international classification of neurodevelopmental disorders.

From a neuropsychological perspective, spelling involves several complex cognitive systems that must function in a coordinated manner. The dual-route model developed by Ellis and Young (1988) and later adapted by Sprenger-Charolles distinguishes two main routes for spelling: the phonological route (assembly) and the lexical route (addressing).

The phonological route allows for the conversion of phonemes into graphemes according to the phoneme-grapheme correspondence rules. This route is particularly engaged for writing new words, pseudo-words, or regular words. It requires good phonological awareness and mastery of the phoneme-grapheme correspondences of the language.

🧠 Neuroanatomical Substrates

Neuroimaging research reveals that dysorthography involves dysfunctions in several brain regions: Broca's area (language production), the angular gyrus (interface between sounds and letters), and the superior temporal regions (phonological processing). These findings guide rehabilitation strategies towards multisensory approaches.

The lexical route relies on the global recognition of words stored in the internal orthographic lexicon. This route is essential for the spelling of irregular words, homophones, and words with orthographic specificities that cannot be deduced from their phonological form.

The normal development of spelling follows a predictable progression, passing through several stages: the logographic phase (global recognition of a few words), the alphabetic phase (progressive mastery of phoneme-grapheme correspondences), and the orthographic phase (automation and development of the orthographic lexicon). Dysorthography disrupts this normal development by affecting one or more of these routes.

🎯 Key Points - Neuropsychological Bases

  • Dual pathway: phonological (assembly) and lexical (addressing)
  • Phonological awareness: foundation of the assembly pathway
  • Orthographic lexicon: storage of orthographic forms
  • Sequential development: logographic → alphabetic → orthographic
  • Neurobiological basis: dysfunctions in language networks

2. 🔍 Classification of Types of Dysorthography

The classification of types of dysorthography is based on the dual pathway neuropsychological model and allows for precise guidance of therapeutic intervention. This typology is essential for adapting rehabilitation strategies to the specific profiles of each patient and optimizing the effectiveness of care.

Phonological Dysorthography

Phonological dysorthography results from a deficit in the assembly pathway, characterized by difficulties in phoneme-grapheme conversion. Patients exhibit deficient phonological awareness, manifesting as difficulties in segmenting words into smaller sound units and manipulating these units.

Typical errors include omissions of phonemes ("arbre" → "abre"), additions ("partir" → "paretir"), substitutions of similar phonemes ("chapeau" → "sapeau"), and inversions ("pour" → "poru"). These errors often render the productions phonetically implausible, meaning they do not adhere to the phoneme-grapheme correspondence rules of the French language.

💡 PRACTICAL ADVICE

To identify phonological dysorthography, systematically analyze errors in dictation of pseudo-words. These invented words can only be written through the phonological pathway, immediately revealing difficulties in phoneme-grapheme conversion. The use of tools like COCO THINKS allows for progressive training of phonological awareness.

Surface (Lexical) Dysorthography

Surface dysorthography or lexical dysorthography is characterized by a deficit in the addressing pathway, with an alteration of the orthographic lexicon. Patients experience particular difficulties with irregular words, grammatical and lexical homophones, as well as words containing silent letters or orthographic peculiarities.

Typical errors are phonetically plausible but orthographically incorrect: "femme" written as "fame", "monsieur" written as "meusieu", or confusions between homophones like "a/à", "son/sont", "et/est". These patients can generally write regular words and pseudo-words correctly, as their phonological pathway is preserved.

This type of dysorthography may sometimes go unnoticed in the early years of schooling, as teaching favors regular words. Difficulties become more apparent with the increasing complexity of vocabulary and the massive introduction of irregular words in school texts.

👨‍⚕️ CLINICAL EXPERTISE
Differential Diagnosis: Dysorthography vs Surface Dyslexia

The distinction between isolated surface dysorthography and surface dyslexia-dysorthography requires a careful assessment of reading skills. Some patients may read correctly through semantic or contextual compensation while exhibiting marked spelling difficulties.

Recommended Assessment Protocol:
  • Reading irregular words under time constraints
  • Dictation of irregular vs regular words
  • Assessment of reading comprehension
  • Analysis of compensation strategies

Mixed Dysorthography

Mixed dysorthography combines deficits from both pathways, phonological and lexical, often representing the most severe form of the disorder. Patients exhibit both difficulties in phoneme-grapheme conversion and issues with the orthographic lexicon, generating a complex profile that requires intensive and differentiated therapeutic intervention.

This form of dysorthography produces all types of errors: phonetically implausible errors on regular words and pseudowords, regularization errors on irregular words, confusions of homophones, and marked grammatical difficulties. The prognosis is generally more reserved, requiring early and sustained management.

📊 Evaluation Tools by Type

Phonological Dysorthography: Dictation of pseudo-words, phonological awareness tests, analysis of conversion errors.

Surface Dysorthography: Dictation of irregular vs regular words, evaluation of homophones, spelling lexicon tests.

Mixed Dysorthography: Complete battery including all previous tests plus evaluation of cognitive load in dual-task.

3. ⚠️ Analysis of Types of Spelling Errors

The qualitative analysis of errors is the core of the speech therapy evaluation in dysorthography. This approach, complementary to standardized tests, allows for precise identification of failing mechanisms and guides therapeutic intervention. A rigorous classification of errors reveals the strategies used by the patient and the underlying cognitive processes.

The analysis of errors must be conducted on different types of linguistic material: isolated words, sentences, short texts, and in various modalities (dictation, delayed copying, spontaneous production). This diversity allows for understanding dysorthography in its complexity and avoids hasty conclusions based on a single type of test.

Phonological Errors

The phonological errors reflect difficulties in processing the sound units of the language and their conversion into graphic units. These errors can be categorized according to their nature: omissions, additions, substitutions, or inversions of phonemes. Each type of error provides information about specific difficulties in the phonological system.

The omissions involve the removal of one or more phonemes in the target word ("arbre" → "abre", "important" → "iportant"). These errors may preferentially affect certain positions in the word (complex consonant onsets, syllabic codas) or certain types of phonemes (fricative consonants, consonant clusters).

The additions correspond to the insertion of additional phonemes ("partir" → "paretir", "classe" → "calasse"). These errors may reflect difficulties in syllabic segmentation or strategies for simplifying complex phonological structures.

🎯 Classification of Phonological Errors

  • Omissions: deletion of phonemes (consonants/vowels)
  • Additions: insertion of extraneous phonemes
  • Substitutions: replacement with similar phonemes
  • Inversions: swapping the order of phonemes
  • Simplifications: reduction of complex consonant clusters

Substitutions involve replacing one phoneme with another, often phonetically similar ("hat" → "sahat", "gift" → "gafit"). Analyzing the distinctive features involved (voicing, place of articulation, manner of articulation) provides insight into the precise nature of phonological difficulties.

Inversions concern the swapping of adjacent or distant phonemes ("for" → "fro", "cheese" → "ceese"). These errors may reflect difficulties in phonological sequencing or phonological working memory disorders.

Lexical and Orthographic Errors

Lexical errors specifically concern the spelling of irregular words and reveal a deficit in the orthographic lexicon. These errors are characterized by regularizations: the patient applies regular phoneme-grapheme correspondence rules to words that have orthographic specificities.

Errors involving silent letters are a sensitive indicator of the development of the orthographic lexicon ("time" → "tim", "finger" → "fing"). Mastery of these elements requires specific memorization of the orthographic form of the word, which cannot be deduced from its phonological form.

🔍 EXPERT ANALYSIS

The analysis of errors on homophones reveals the patient's ability to use the morpho-syntactic context to disambiguate spelling. A low performance suggests either a lexical deficit or associated grammatical difficulties. The exercises of COCO THINKS allow for targeted training of these skills.

Confusions of homophones represent a particular challenge in French, requiring the integration of spelling, lexical, and grammatical information ("a/à", "son/sont", "ou/où"). These errors can reflect both a deficit in the orthographic lexicon and a weakness in morpho-syntactic skills.

Grammatical and Morphological Errors

Grammatical errors concern the application of agreement and conjugation rules, revealing difficulties in morpho-syntactic processing. These errors can coexist with phonological or lexical dysorthography, or constitute an isolated disorder sometimes called "grammatical dysorthography".

Agreement errors include gender and number agreements in the noun phrase ("les chats noirs" → "les chat noir"), subject-verb agreement ("les enfants jouent" → "les enfants joue"), and past participle agreement. The analysis must distinguish systematic errors from fluctuating errors, the latter suggesting knowledge of the rule but difficulties in application.

Conjugation errors may involve inflectional morphology ("ils mangent" → "ils mange") or the choice of verb tenses. A fine analysis must consider the complexity of verb forms (auxiliaries, irregular forms, tense agreement) and the associated cognitive load.

📊 ANALYSIS TOOL
Spelling Error Analysis Grid

A systematic analysis grid allows for quantifying and qualifying errors to guide intervention. It should include mutually exclusive categories and cover all spelling processes.

Main Categories:
  • Phonologically implausible errors (assembly route)
  • Regularization errors (addressing route)
  • Errors of lexical and grammatical homophones
  • Agreement and conjugation errors
  • Lexical segmentation errors

4. 📝 Diagnostic Assessment of Dysorthographia

The assessment of dysorthographia requires a multidimensional approach combining standardized tests, qualitative analyses, and clinical observations. This diagnostic process aims to precisely identify the failing mechanisms, quantify the severity of the disorder, and establish a differential cognitive profile to guide therapeutic intervention.

The assessment process must follow a logical progression: detailed anamnesis, evaluation of cognitive prerequisites, systematic exploration of spelling skills, and differential analysis with associated disorders. This methodical approach ensures the reliability of the diagnosis and the relevance of therapeutic recommendations.

Anamnesis and Development Exploration

The anamnesis is the first step of the assessment, allowing for the tracing of the patient's developmental history and identifying risk factors. The exploration should cover pre-linguistic development (babbling, first words), the acquisition of oral language, and the evolution of written language skills since the start of schooling.

Family history of written language disorders should be systematically investigated, as dysorthographia has a significant hereditary component. The school history, the pedagogical adaptations implemented, and the evolution of performance in different subjects provide crucial information about the learning profile.

📋 Structured Anamnesis Questionnaire

Language development: age of first words, combinations of words, persistent phonological difficulties.

Learning to read and write: age of starting to read, learning method, evolution of skills.

Schooling: repeating a year, adaptations, difficulties in different subjects, school fatigue.

Family history: DYS disorders in siblings/relatives, family school difficulties.

Evaluation of Cognitive Prerequisites

The evaluation of cognitive prerequisites is essential to differentiate dysorthography from other disorders that may affect spelling. Intellectual evaluation, conducted by a psychologist, helps exclude intellectual disability and identify any associated attentional or executive disorders.

Phonological awareness must be thoroughly evaluated, forming the basis of the assembly route. The tests should cover different levels of processing: syllabic awareness, rhyming awareness, and phonemic awareness. Tools like phoneme deletion, addition, or inversion tests allow for a fine evaluation of these skills.

Working memory, particularly in its phonological component, plays a crucial role in spelling. Tests of digit span, repetition of pseudo-words, and updating in working memory provide information about these abilities. Difficulties in this area may explain certain spelling errors and guide rehabilitation strategies.

🎯 Mandatory Evaluation Areas

  • General intelligence: total IQ and cognitive profile
  • Phonological awareness: syllabic, rhyming, phonemic
  • Working memory: phonological loop and central executive
  • Attention: sustained, selective, divided
  • Executive functions: inhibition, flexibility, updating

Standardized Spelling Tests

Standardized tests are the central objective element of the evaluation, allowing for quantification of performance and comparison with developmental norms. The choice of tests should be adapted to the patient's age and diagnostic hypotheses, prioritizing scientifically validated and regularly calibrated tools.

The dictation of words represents the reference test, which should include different types of stimuli: regular words, irregular words, and pseudo-words. This diversity allows for separate exploration of the assembly and addressing routes, revealing the specific profile of dysorthography. The words must be controlled for frequency, length, and orthographic complexity.

The dictation of sentences and texts evaluates spelling in a more natural context, where grammatical constraints and the cognitive load associated with simultaneously producing meaning and form come into play. This modality often reveals hidden difficulties in the evaluation of isolated words and provides insight into the functional impact of the disorder.

⚡ DIAGNOSTIC INNOVATION

The use of digital tools like COCO THINKS allows for precise recording of reaction times and strategies used, providing additional information to traditional tests. This data significantly enriches qualitative analysis and finely guides intervention.

Evaluation of Spontaneous Written Production

The evaluation of spontaneous written production complements standardized assessment by revealing spelling skills in a real communication context. This evaluation allows for the observation of avoidance strategies, the quality of self-correction, and the impact of cognitive load on spelling performance.

The production task can be free (telling about one's vacation) or semi-directed (describing an image, continuing a story). The analysis should focus on lexical richness, syntactic complexity, and of course spelling, taking into account the age and school level of the patient.

🎯 EVALUATION PROTOCOL
Complete Evaluation Battery for Dysorthographia

A standardized evaluation protocol ensures the completeness of the assessment and the comparability of results between patients and over time.

Recommended Sequence (3 sessions) :
  • Session 1 : Anamnesis, global cognitive evaluation
  • Session 2 : Standardized spelling tests, phonological awareness
  • Session 3 : Written production, reading assessment, synthesis

5. 🎯 Intervention Strategies and Speech Therapy Rehabilitation

The intervention in dysorthographia is based on scientifically validated principles and must be adapted to the specific profile of each patient. The effectiveness of rehabilitation depends on the accuracy of the diagnosis, the timeliness of the intervention, the intensity of the training, and the involvement of the family and school environment.

Modern therapeutic approaches favor a multimodal intervention combining explicit training of deficient skills, compensatory strategies, and the use of innovative technological tools. This comprehensive approach optimizes the chances of progress and promotes the patient's autonomy in their learning.

The integration of applications like COCO THINKS and COCO MOVES into the therapeutic protocol adds a playful and motivating dimension, essential for maintaining the patient's engagement over time. These tools allow for regular and progressive training, perfectly complementing traditional speech therapy sessions.

Rehabilitation of the Phonological Route

The rehabilitation of the phonological route specifically targets deficits in phonological awareness and phoneme-grapheme conversion. This approach is particularly indicated in phonological dysorthographies and often constitutes the first therapeutic step in mixed forms.

The work on phonological awareness must follow a developmental progression: syllabic awareness (syllable segmentation, counting), intra-syllabic awareness (onset-rime), and then phonemic awareness (identification, manipulation, synthesis of phonemes). Each step must be mastered before moving on to the next.

The training of phoneme-grapheme correspondences requires a systematic and explicit approach. The progression must respect the frequency of correspondences in the French language, starting with one-to-one correspondences (one phoneme = one grapheme) before addressing complex correspondences (phonemes with multiple possible transcriptions).

🎵 Effective Multisensory Methods

Borel-Maisonny Method: gesture-sound-letter association to anchor phoneme-grapheme correspondences.

SMSM Method: Simultaneous Multi-Sensory Multi-Structured, using all sensory channels.

Davis Method: clay modeling to create a three-dimensional representation of letters.

COCO THINKS: adaptive digital exercises for regular phonological training.

Multisensory techniques are particularly effective for consolidating learning. The simultaneous association of visual (seeing the letter), auditory (hearing the sound), kinesthetic (tracing the letter), and articulatory (pronouncing the sound) modalities creates robust mnemonic networks and promotes automation.

Development of Orthographic Lexicon

The development of the orthographic lexicon is the main objective of the rehabilitation of surface dysorthographies. This approach aims to enrich and stabilize the overall memorized word stock, allowing for automated orthographic recognition and production.

The selection of words to work on should prioritize frequent and functional words, using validated frequency lists such as the Lexique base or Manulex. Progression should also take into account the patient's age, school level, and interests to maintain motivation.

Memory techniques should be varied and adapted to the cognitive profile of the patient. Visual associations (the "words within words" method), mnemonic devices, morphological families, and mental visualization are effective tools for permanently anchoring the spelling of irregular words.

🎯 Lexical Memorization Strategies

  • Rhythmic spelling: syllabic segmentation with rhythmic tapping
  • Words within words: "in dangerous, there is angel and them"
  • Visual associations: mental images related to spelling
  • Morphological families: grouping by common roots
  • Mnemonic devices: memorable phrases or stories

Grammatical and Morphological Approaches

The grammatical approach is essential for addressing difficulties in agreement and conjugation, often associated with dysorthography. This intervention requires a prior understanding of fundamental grammatical concepts: word classes, syntactic functions, and morphological relationships.

Teaching agreement rules must be explicit and structured, with a progression from simple agreements (determiner-noun) to complex agreements (past participle with auxiliary être/avoir). Each rule should be accompanied by verification and self-correction strategies.

🔧 THERAPEUTIC TOOL

The "agreement chain" is an effective strategy: identify the giver (who imposes the agreement), mentally or physically trace the link to the receiver (who agrees), apply the rule. This visualization of grammatical relationships facilitates the automation of agreements. COCO THINKS offers interactive exercises based on this approach.

Working on conjugation must integrate a morphological approach, identifying regularities and verb families. The automation of frequent endings and the memorization of irregular forms are the two pillars of this rehabilitation.

Metacognitive and Self-Correction Strategies

The development of metacognitive strategies allows the patient to gradually become autonomous in managing their spelling difficulties. These strategies include planning writing, self-monitoring during production, and systematic self-correction.

Teaching specific proofreading strategies is essential. Effective proofreading requires several targeted passes: a first pass for the general meaning, a second for lexical spelling, a third for grammatical agreements. This systematic approach optimizes the detection and correction of errors.

🎓 STRUCTURED PROGRAM
Intensive Rehabilitation Protocol (12 weeks)

A structured 12-week program allows for significant and measurable progress, provided a minimum frequency of 3 sessions per week is maintained.

Temporal Organization:
  • Weeks 1-4: Phonological awareness and basic correspondences
  • Weeks 5-8: Spelling vocabulary and common words
  • Weeks 9-12: Grammatical rules and self-correction strategies
  • Throughout: Daily use of COCO THINKS (15-20 min)

6. 🏫 School and Educational Accommodations

School accommodations are an essential aspect of managing dysorthography, allowing for the compensation of persistent difficulties and preserving the student's self-esteem. These adaptations must be individualized, evolving, and based on the recommendations of the High Authority of Health (HAS) and the National Education.

The implementation of accommodations requires a close collaboration between the educational team, the speech therapist, the family, and possibly the school doctor. This coordination ensures the coherence of the adaptations and their acceptance by all parties involved in the child's education.

Accommodations should aim for a dual objective: to allow the student to demonstrate their skills in subjects not directly related to spelling, and to maintain adapted requirements in French to promote progress. This balanced approach avoids both over-accommodation and under-accommodation.

Accommodations during Assessments

Assessment accommodations often represent the primary request from families and are indeed an important lever for objectifying the student's skills. These adaptations must be proportional to the severity of the disorder and evolve based on the progress made in rehabilitation.

The use of a computer with spell checker is the reference accommodation for severe dysorthographies. This tool allows for effective compensation while maintaining the requirement for written production. Training the student in the optimal use of the spell checker is an integral part of the support.

The extension of time (generally 1/3 additional time) compensates for writing fluency difficulties and allows the student to implement their self-correction strategies. This measure is particularly beneficial for students who have developed good metacognitive strategies.

📊 Grading Adjustments According to Severity

Light (< 10th percentile) : No spelling penalty outside of dictation, 1/3 time if needed.

Moderate (< 5th percentile) : Computer + spell checker, exam secretary occasionally.

Severe (< 1st percentile) : Systematic secretary, oral assessments preferred.

The human assistance (exam secretary) may be necessary in very severe dysorthographies, particularly during high-stakes exams. This exceptional measure must be accompanied by prior training to optimize the student-secretary collaboration.

Daily Pedagogical Adaptations

The daily pedagogical adaptations concern all classroom practices and require raising awareness among the educational team about the specifics of dysorthography. These adjustments, often simple to implement, can significantly improve the student's school experience.

The differentiation of evaluation methods allows for valuing the student's skills: prioritizing oral assessments in history-geography, offering multiple-choice questions in science, using labeled diagrams in life sciences. This approach often reveals skills masked by spelling difficulties.

The adaptation of materials facilitates access to learning: fill-in-the-blank texts to avoid