Can the first letter advantage be shaped by script-specific characteristics?

We examined whether the first letter advantage that has been reported in the Roman script disappears, or even reverses, depending on the characteristics of the orthography. We chose Thai because it has several "nonaligned" vowels that are written prior to the consonant but phonologically follow it in speech (e.g., แฟน <ε:fn> is spoken as /fɛ:n/) whereas other "aligned" vowels are written and spoken in a corresponding order, as occurs in English (e.g., ฟาก <fa:k> is spoken as /fa:k/). We employed the forced choice decision paradigm of Adelman, Marquis, and Sabatos-DeVito (2010) to examine letter identification across letter positions in 3- and 4-letter Thai legal nonword pairs. Results showed an advantage of the initial letter position for the aligned legal nonwords, as occurs in Roman script (e.g., Scaltritti & Balota, 2013). However, for the nonaligned legal nonwords, an advantage of second letter position was found which is in line with the characteristics of these types of stimuli: the critical initial consonant occurs in the second letter position. These results highlight the importance of the initial phonological letter in Thai, which is crucial for mapping orthography to phonology and for lexical access. In conclusion, these results illustrate that initial letter advantage can be shaped by the characteristics of the orthography. (PsycINFO Database Record (c) 2018 APA, all rights reserved).