Abstract Thai has its own distinctive alphabetic script with syllabic characteristics
as it has implicit vowels for some consonants. Consonants are written in a linear
order, but vowels can be written non-linearly above, below or to either side of the
consonant. Of particular interest to the current study are that vowels can precede the
consonant in writing but follow it in speech, hence a mismatch between the spoken
and written sequence occurs, for example ‘flat’ is spoken as /bɛ:n/ or in a
more severely misaligned example where the vowel operates across syllables the
word ‘insect’ is spoken as /m(a)lɛ:ŋ/. In order to investigate if there is a
processing cost associated with this discrepancy between spoken and written
sequence for vowels and the implications this has in relation to the grain size used
when reading Thai, eye movements of adults reading words with and without
misaligned vowels in sentences using the EyeLink II tracking system was conducted.
Twenty-four university students read 50 pairs of words with misaligned and
aligned vowel words matched for length and frequency embedded in same sentence
frames. In addition, rapid naming data from forty adults was collected. Data from
forty children 6;6–8;6 years old reading and spelling comparable words was also
collected and analysed for errors. Results revealed a processing cost due to the more
severely misaligned words where the vowel operates across the syllable, and gives
support for a syllabic level of segmentation rather than phonemic for reading and
spelling in Thai adults and children.
Keywords Development · Grain size · Reading · Spelling · Thai ·
Vowels