UC San Diego

Prelingually and profoundly deaf individuals learn to read without complete access to the sounds of language. Nevertheless, many become proficient readers, and the neurocognitive underpinnings of deaf readers’ processes differ from those of hearing readers, particularly in orthographic processing. In English, morphological structure is relatively orthographically transparent, unlike its opaque phonological system. For skilled readers, who frequently encounter morphologically complex words, morphological awareness is vital for reading and vocabulary development. This skill may be especially important for deaf readers, who rely more on spelling-to-meaning mappings than sound-to-meaning mappings. This dissertation presents three experiments on morphological awareness and its relationship to reading skill among deaf readers. Chapter 1 examines the relationship between reading subskills (vocabulary, spelling, and morphology) and reading comprehension in similarly skilled deaf and hearing readers. Chapter 2 uses event-related potentials (ERPs) to study brain responses to morphological structure in single-word processing. Chapter 3 employs eye-tracking to explore the processing of morphological structure in the parafovea during sentence reading for both groups. The results show that morphology plays a distinct role for deaf readers, evident primarily in those with high morphological awareness skills. Deaf readers with higher morphological awareness exhibited a strong relationship between morphology assessments and reading comprehension, unlike deaf readers with low morphological awareness or hearing readers at any morphological awareness level. Differences were also observed in online processing of morphological structure, including neural responses and eye movement behaviors. These findings suggest that including targeted morphology instruction in reading interventions could enhance reading outcomes for deaf readers, providing them with an accessible and efficient skill set for reading development.