Is academic language use a separate dimension in beginning writing? Evidence from Korean

• We studied academic language use and its relation to other dimensions of writing.
• Academic language was part of substantive quality dimension.
• Comprehension and spelling were related to substantive quality of written composition.
• Transcription skills were related to the productivity of written composition.

In the present study, we examined whether children's use of academic language (vocabulary and connectives) were a dissociable dimension from quality and productivity dimensions of written composition, and how language and literacy predictors are related to various writing dimensions for beginning writers in Korean (N = 156). Results showed that academic vocabulary and connectives were better described as indicators of the substantive quality dimension, not a separate dimension. Children's language and reading comprehension skills as well as spelling skill were uniquely related to the quality dimension of written composition. Children's transcription skills such as spelling and handwriting automaticity were uniquely related to the productivity dimension of written composition. These results suggest that the extent to which children use academic language in written composition contributes to the quality aspect of written composition, and unique language and literacy predictors differ for different dimensions of written composition for Korean beginning writers.