Phonology is involved in Delayed Chinese Character Copying

Background
Writing is crucial for students to fulfil various task requirements in traditional Chinese classrooms. Students with written language disorder, who failed in writing that negatively impacted their academic performance, are frequently associated with psychological and social problems. Investigating the cognitive mechanism of writing can provide basis for the identification of possible deficits underlying the disorder. Consequently, clinical assessments can be designed accordingly to achieve early identification and intervention. Nevertheless, assessing writing is not easy. Common tasks such as writing-to-dictation, which usually yielded very low accuracy, and immediate copying task, which usually yielded results driven predominantly by orthographic effects, are not preferred. In the current study, a delayed copying task is used in attempt to solve the problem.

Methods
Twenty native Cantonese-speaking right-handed undergraduate students receiving mainstream education in Hong Kong since kindergarten were recruited. No visual, cognitive, learning or motor impairment was reported.
Forty pairs of phonetically regular and irregular Chinese characters were selected from the Hong Kong Corpus of Chinese Newspapers (Leung & Lau, 2010). Phonetic compounds with free-standing corresponding phonetic radicals located at the right or bottom positions were identified. The pairs were matched according to their character frequencies, age of acquisition, number of strokes, radical frequencies, number of homophones, imageability and semantic radical transparency (p > .05 in paired t-tests).
A delayed Chinese character copying task modified from Anderson et al. (2013) was conducted by using a handwriting software package, Ductus (Guinet & Kandel, 2010). For each trial, two characters from the stimuli set were shown, one on the left and the other on the right, for two seconds. Upon characters removal, a probe was given to instruct the participants to write either the left or right previously shown character. They were asked to write without merging successive strokes. The latency of each stroke onset and offset was collected.

Results
Linear mixed-effect models with maximal model structure (Barr et al., 2013) was used to investigate the effect of the variables in predicting the writing duration (WD) of the first (semantic) radical, measured as the duration from the stroke onset time of the first radical till the start point of the first stroke of the second (phonetic) radical.
The results showed that WD significantly increased with number of strokes of characters (14.38±2.57) and decreased with presentation order (-0.10±0.04). It also significantly decreased with frequency of first radical (-131.19±17.03) and regularity (-32.65±14.64).

Discussion
Shorter WD observed among later presented characters is probably due to the participants’ improved familiarity of the task. The significant regularity effect after controlling for radical frequency observed in the WD supported that phonological information associated with the characters is involved in the writing process (Lau, 2020). It also supported that central processing cascade over peripheral processing (Delattre et al., 2006; Zhang & Feng, 2017).
It is proposed that the delayed copying task is an applicable clinical tool with high potentials in identifying the deficits in central and/or peripheral processing that underly the written language disorder in comparison to writing-to-dictation task and immediate copying task.