Orthographic Error Forms in a Dyslexic Teenager: A Psycholinguistic Approach to Letter Formation and Cognitive Processing

Abstract

Orthographic error patterns provide valuable evidence of the psycholinguistic processes underlying written language production in individuals with dyslexia. This study examines the orthographic error patterns produced by an Indonesian adolescent with dyslexia from a psycholinguistic perspective. Employing a descriptive qualitative single-case study design, the research involved a 15-year-old ninth-grade student diagnosed with dyslexia. Data were collected over five months through document analysis of handwritten texts, classroom observation, and semi-structured interviews. A total of 43 written words obtained from sentence-construction and dictation tasks were analyzed using a linguistic classification framework based on phonological and morphological processes. The findings identified nine orthographic error patterns, with consonant substitution (24%) occurring most frequently, followed by vowel substitution (16%), vowel omission (14%), consonant addition (12%), consonant omission (12%), syllable omission (8%), vowel-to-consonant substitution (6%), consonant-to-vowel substitution (4%), and vowel addition (2%). From a psycholinguistic perspective, these patterns suggest systematic difficulties in phonological encoding, grapheme–phoneme mapping, phonological working memory, and morphological processing during written language production. The findings support previous research on orthographic processing in dyslexia while extending its application to the Indonesian language context through a systematic classification of orthographic errors in an adolescent with dyslexia. Although limited to a single participant, this study contributes to understanding orthographic processing in Indonesian adolescents with dyslexia and provides implications for developing explicit phonological, morphological, and multisensory literacy instruction.