Unpacking the Relation Between Oral Language and Written Composition: A Meta-Analysis

Oral language underpins written composition, establishing a relation between the two constructs; however, a comprehensive understanding of the factors moderating this relation remains to be fully explored. This meta-analysis investigates the relation between oral language and written composition, with a particular focus on identifying the factors that influence its relation. Moderators of grade level, language learner status, developmental language disorder status, orthographic depth, linguistic grain sizes (e.g., vocabulary, discourse skills), and measurement features for both constructs were considered. Measurement features for oral language encompassed format (oral vs. written), outcome (quality vs. productivity), modality (expressive, productive, or mixed), and the distinction between normed and research-developed tasks. For written composition, genre (informational vs. narrative), dimensions (e.g., quality, productivity), and the distinction of normed tasks were considered. A total of 104 studies involving 214,734 participants met inclusion criteria and revealed a moderate but significant correlation between oral language and written composition (r = .34). Results indicated that the relation between oral language and written composition strengthened as students progressed through grade levels and was more pronounced among foreign language learners compared to native speakers. Furthermore, the relation between oral language and written composition was particularly strong when the latter was assessed through the dimensions of quality, vocabulary, and fluency. This meta-analysis provides a comprehensive quantitative synthesis, underscoring the importance of considering individual factors and measurement features. The findings have practical implications for literacy instruction and future research aimed at closing gaps in our understanding of oral language and written composition.