Assessment and Intervention of Letter Knowledge With Children With Developmental Language Disorder: A Systematic Review

Purpose: Letter knowledge, including letter-name and letter-sound recognition and identification, and writing, is foundational for decoding and reading development. Children with developmental language disorder (DLD) are at risk for persistent literacy difficulties; however, assessment and intervention practices for this population remain underexplored. This systematic review synthesizes research on letter-knowledge assessment and intervention in children with DLD. Method: Studies examining English-language assessment or intervention of letter knowledge among children aged 3–18 years with DLD or specific language impairment were systematically identified across multiple databases. Two reviewers independently screened all studies and extracted data using a standardized protocol. A narrative synthesis summarized patterns in assessment focus, intervention, and instructional approaches. Results: Assessment studies most often examined letter-name and letter-sound identification, while recognition and writing tasks were rarely included. Only one study assessed all five subskills. Standardized measures predominated, with few experimental tools. Eight intervention studies provided letter-knowledge instruction. Some focused solely on letter knowledge, whereas most integrated it with phonological awareness or broader literacy instruction. Across interventions, letter-sound identification was emphasized, with variation in setting and dosage. Conclusions: Research on letter knowledge in children with DLD mainly targets letter naming and sound identification, with limited attention to recognition and writing. Because recognition emerges earlier and identification later, assessing all five skills may not always be desirable. Task selection, including writing, should be intentional, and this review article outlines tools to guide decisions.