Orthographic facilitation of vocabulary learning in populations with and without hearing loss
Vocabulary acquisition is a life-long process that is known to play a crucial role in children’s communication, reading and literacy acquisition, and academic success. It is therefore not surprising that several attempts have been made to identify instructional strategies to assist with vocabulary learning. One such strategy involves the provision of spellings when introducing new words to children. Researchers have established that the presence of orthography has a facilitatory effect on learning the pronunciations and meanings of new words in school-aged children (e.g., Ricketts, Nation, & Bishop, 2007). The aim of this thesis was to investigate the implementation of the orthographic facilitation effect in children and adults learning new words. Primary school children encounter new words in classrooms every day and must learn and add these words to their mental lexicon to build vocabulary skills. Children with hearing loss face particular challenges in acquiring spoken vocabulary due to impoverished linguistic input because of hearing loss and because of weak phonological skills. Another instance of impoverished input can be the result of learning in a noisy classroom or listening environment, even when word learners are adults. In a series of experiments, novel words were paired with pictures of vintage objects and taught with or without spelling to children from different grades of primary school (Chapter 2), children with or without hearing loss (Chapter 3) and adults learning in quiet versus noisy environments (Chapter 4). Behavioural and eye tracking measures were used to assess word learning and to compare learning and retention of words taught with and without spellings. The results provide evidence for the effectiveness of this vocabulary instruction strategy in different populations. The findings are related back to earlier studies of orthographic facilitation and theoretical accounts of possible mechanisms that may underlie the orthographic facilitation effect (Chapter 5).