Importance of phonological and orthographic processing skills for English literacy abilities in English monolingual, Chinese-English bilingual, and English monolingual learners with dyslexia

Phonological and orthographic processing skills are important underlying skills for English word reading and spelling in English monolingual individuals. Yet, there is still much to learn about these skills in other specific populations, such as individuals learning English with another language and individuals who have difficulty acquiring English literacy skills. This thesis addresses this issue by examining phonological and orthographic processing skills in Chinese-English bilingual children and adults, English monolingual children and adults, and English monolingual children with dyslexia. More specifically, we investigate the importance of these skills for English word reading and spelling across these different language groups.

Phonological and orthographic processing skills were assessed and their importance for English word reading and spelling was examined in younger (8-9 years) children, older (11-12 years) children and adults (19-20 years) from different language backgrounds: English monolingual, English first language (L1)-Chinese second language (L2) and Chinese L1-English L2. Results showed that proficiency in English phonological and orthographic processing skills was dependent on age and language background status. Both English monolingual and English-L1 children had better phonological processing skills compared to the Chinese-L1 children, and the English monolingual adults had better phonological processing skills than the bilingual adults. In contrast, the younger bilingual children had better orthographic processing skills compared to the English monolingual children, but there were no group differences in the older children and adults. Furthermore, different skills contributed to English word reading and spelling for each language background group and within each age group. Orthographic processing was the only significant predictor of word reading and spelling for the English monolingual children and adults. However, phonological processing skills were important for word reading for the bilingual children and adults. For spelling, phonological skills were a significant predictor for the younger bilingual children and orthographic skills were important for the older bilingual children, but neither skill contributed significantly for the bilingual adults. The finding that different skills are important for the different language groups suggests an influence of learning a second language on English literacy acquisition.

The proposal that children with dyslexia have a differential pattern of phonological and orthographic skills, with poorer phonological skills relative to their orthographic skills (e.g., Stanovich & Siegel, 1994), similar to that of Chinese-English bilingual children was then explored. The phonological and orthographic skills of English monolingual children with dyslexia were compared to those of chronological age matched and reading-age-matched English monolingual, Chinese L1-English L2, and English L1-Chinese L2 children, and the relationships between phonological and orthographic skills and English word reading and spelling in the dyslexic children were investigated. Results showed that the children with dyslexia were as proficient as the reading-age-matched English monolinguals in terms of their phonological and orthographic skills and hence, were not similar in profile to the Chinese-English bilingual children. In addition, similar to the English monolinguals, only orthographic skills contributed significantly to word reading and spelling for the children with dyslexia.

Phonological and orthographic skills are important for Chinese-English bilingual, dyslexic and typically developing English monolingual individuals for English word reading and spelling. However, group differences in skill proficiencies, as well as differences in the extent to which phonological and orthographic skills are relied upon, imply that different populations approach English literacy tasks in different ways. An important implication of these findings is that these differences need to be taken into account before applying models of literacy development to populations other than English monolinguals. Further theoretical and practical implications of these findings are discussed.