Thai, a tonal language, has a distinctive alphabetic orthography. In the current study, spelling development in Thai children is examined. A number of predictions about spelling development and types of errors are made based on previous research on other orthographies in conjunction with the characteristics of Thai language and its orthography. Spelling of words was assessed in 60 Thai children ranging in age from 7 years to 9 years from Grade(s) 1, 2, and 3. After 4 months of school, Grade 1 children achieved 32% correct, Grade 2 children 85% correct, and Grade 3 children 87% correct for word spelling. Spelling performance rapidly increased between the youngest Grade 1 children and the older children with relatively few errors made by the older children. We found striking commonalities with other orthographies previously studied and also orthography-specific characteristics emerged. Homophonous consonants, consonant clusters, visually similar letters, vowel length, and other irregularities in the orthography posed significant challenges to young learners. As predicted the complex vowel combinations and tone system also proved problematic.
Winskel, H 2010, 'Spelling development in Thai children', Journal of Cognitive Science, vol. 11, pp. 7-35.