Traditionally, literacy, and speech production have been investigated separately. Studies of development demonstrate that children are able to meet the challenge of language learning across modalities, and that adults may experience difficulties in one or both modalities. Yet, it is rare to find a conceptual connection between these two processes. I argue that speaking and reading actually share important mechanisms. Specifically, orthographic characteristics of written words influence spoken as well as written language, as indicated by measures of both explicit and implicit language processing. These effects can be quantified by examining speech movement variability. An important question regarding both limb and speech motor variability is whether it is interpreted as facilitating or inhibiting the process of learning. New lines of research may explore this question by quantifying the depth of learning when stimuli are produced with greater stability or greater variability. The developmental progressions of speaking and reading also contain important parallels, which are manifest differently in individuals with varying degrees of language and reading skills. This is an important and timely issue, as it can promote theoretical accounts of language processing and respond to the clinical reality that many individuals demonstrate both spoken and written language difficulties.
Saletta, M. (2015). Literacy transforms speech production. Frontiers in Psychology, 6. https://doi.org/10.3389/fpsyg.2015.01458