Investigation of Individual Differences in Single-Word Spelling Skill in Adult Speakers of Mandarin: An Orthographic Processing Explanation

The examination of individual differences in spelling ability in adults is potentially theoretically informative but has attracted little research attention. Most of this work has involved speakers of English, and some indicated that orthographic processing may be an important factor that distinguishes better from poorer spellers. The current investigations were carried out in Mandarin, which has a logographic writing system. Because Chinese characters place particularly heavy demands on visual–orthographic processing, adult Mandarin spelling provides a strong test case for orthographic accounts of individual differences in spelling ability. Participants were 54 adult speakers of Mandarin. We used adaptations of the tasks that have previously been used in studies of spelling with English speakers, including assessments of phonological processing, visual memory, character report and reading fluency. We used hierarchical multiple regression to examine the unique contribution of these literacy-related variables to spelling accuracy after controlling for chronological age and single-character identification. We also conducted quantitative error analysis of the participants’ spelling errors, using error categories that distinguish phonologically appropriate errors and orthographic errors. Finally, we conducted item-level logistic regression analyses to examine the influence of number of logographemes per character on spelling accuracy at the individual-participant level. The results of the hierarchical regression analyses examining the influence of the literacy-related variables showed that character report was the strongest predictor of spelling accuracy. Quantitative error analysis of the participants’ spelling errors revealed that the rate of orthographic errors increased with a decrease in spelling accuracy, while the rate of phonological errors (homophone and semi-homophone substitutions) reduced. Item-based analyses based on individual-level logistic regression analyses showed that participants with lower spelling accuracy were more sensitive to the number of logographemes per character. The results are in line with those found in previous studies in English, indicating the importance of orthographic processes in determining spelling ability in adults. We discuss the findings in the light of theories that include orthographic working memory as a late stage in the process of single-word spelling.