Syllable and letter similarity effects in Korean: Insights from the Korean Lexicon Project

Abstract

• Network analysis was used to quantify syllable and letter similarity of Korean words. • Visual lexical decision data for thousands of Korean words were analyzed. • Words in central locations of the syllable similarity space were recognized faster. • Greater letter similarity inhibited word recognition. • Korean readers process syllable and letter information in Hangul in complex ways. The Korean writing system, Hangul, is an alphabetic syllabary which permits a unique opportunity to investigate how both the syllabic and letter similarity structure of the Korean mental lexicon influences lexical processing. We capitalized on the availability of lexical decision behavioral data for thousands of Korean words, and the tools of network science to quantify the similarity structure of Korean words, to investigate the relative and interacting influences of syllable and letter similarity effects on Korean word recognition. Syllable and letter similarity measures were computed at both local and global levels of the lexicon, by considering the immediate neighbors of the target word (i.e., local) and the centrality of the target word with respect to the entire lexicon (i.e., global). Regression analyses showed that both local and global syllable and letter similarity influenced lexical decision performance, revealing a complex pattern of similarity effects where greater local similarity inhibited word recognition, and greater global distinctiveness facilitated word recognition. Furthermore, there were significant interaction effects between syllable and letter levels, suggesting that both syllabic and letter information are processed in an interactive fashion by Korean readers. Our findings demonstrate the importance of adopting computational methods that go beyond standard neighborhood measures and that can quantify the similarity relationships between words at multiple levels.