The Jaw as a Cross-Script Anchor: An Embodied, Grain-Size-Sensitive Model for Literacy Acquisition across Writing Systems

Abstract

A candidate universal anchor for literacy is offered by the jaw’s open-close cycle through its coupling with syllable production—what we term "jaw-drop mapping." Reading science has long treated script-to-sound mapping as a disembodied computation, yet embodied neurocognitive accounts predict that literacy recruits the sensorimotor machinery that originally evolved for speech. Our synthesis provides the first mechanistically explicit account to unify previously disconnected findings from speech-motor, cross-script behavioral, and neural literatures into a set of testable propositions. We propose the Embodied Anchor–Grain-Size Interface Model, comprising five linked propositions (P1–P5). Convergent evidence indicates that the syllable is the maximal phonological unit that is both biomechanically grounded and consciously accessible before literacy. Acquisition cost is determined by the grain size that each writing system demands: phoneme, syllable, or morpheme-syllable. Phonological recoding serves as the shared pivot across scripts; metalinguistic awareness transfers most reliably across languages; and the motor cortex participates functionally in language and print processing, with stronger involvement among second-language users. Like a nautical anchor, the jaw-drop cycle may stabilize early decoding. Critically, no study has directly tested a jaw-anchored curriculum across scripts, and null findings in older remedial readers bound the model’s population validity. We therefore advance this model as a mechanistically coherent, peripherally well-supported, but centrally untested research program and specify a five-study agenda for its decisive test.

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