Development of Language by Hand and Its Connections with Language by Ear, Mouth, and Eye

Contrary to popular conception, language is not a unitary ability. Four functional language systems—(1) aural, (2) oral, (3) reading, and (4) writing—develop on independent trajectories that are interconnected to varying degrees at different stages of development. These interconnected, yet independent, language systems differ on more than modality of input or output. A decade-long research program is described that has focused on the development of the functional writing system and its connections during development with the aural/oral language and reading systems in school-age children. Applications of this research to assessment and educational intervention for specific writing disabilities are discussed.