The mental representations of Hanja: exploring cross-script semantic cohorts in Korean
Keywords: semantic processing
semantic cohorts
writing systems
Korean
bi-scriptal mental representations
orthography

More than half of the Korean lexicon comprises words of Chinese origin. Sino-Korean words, unlike native Korean words, can be written two different ways, using either the native alphabetic script, Hangul, or logographic Chinese characters (called Hanja in Korean). While all Korean words, whether native or Sino Korean, can be written using Hangul, only the latter can additionally be written using Hanja. This means Sino-Korean words have two separate orthographic representations which are crucially equivalent to one other. Previous studies have shown that the mental representations of words take into account such lexical information as the morphology and the phonology as well as the orthography. An open question concerns languages, such as Korean, that have two structurally distinct scripts comprising the writing system, and how the mental lexicon represents the contributions of different scripts. A further complication arises with Korean, as it is often the case that there is more than one Hanja orthographic representation which is equivalent to the Hangul representation. The extensive use of Hanja subsequently resulted in numerous loans into the Korean lexicon, effectively creating two sub-lexicons, one which is native to the language (native Korean), and one which is not (Sino-Korean). This thesis tested whether native Korean speakers’ mental representations of Sino-Korean words encoded the semantics of different Hanja characters, and whether the processing of Sino-Korean was modulated by the size of the semantic cohort. Through a series of four behavioral studies, the status of Hanja characters in the Korean mental lexicon was investigated, and the findings confirmed that lexical processing in Sino-Korean involved the active processing of the semantic contributions of Hanja characters. Furthermore, the data demonstrated that Sino-Korean processing involves semantic access to multiple meanings, as encoded by different Hanja characters. This shows that semantic access is possible across two different scripts within one writing system, and that for Sino-Korean specifically, such semantic access is mediated by the shared representation in Hangul. For each individual Sino-Korean morpheme, a cross-script cohort is generated, comprising the different meanings derived from the semantic contributions of all of the possible Hanja characters that share that particular Hangul representation. In auditory processing of Sino-Korean in particular, lexical access was significantly modulated by the size of this cross-script semantic cohort, with faster response times associated with larger cohort sizes. While these cohorts theoretically exist for all Sino-Korean morphemes, the collective findings across all four experiments seemed to suggest that access to all available meanings was not uniform for all morphemes, highlighting the potentially variable status of individual Sino-Korean morphemes in the Korean mental lexicon. As a result of this empirical investigation, a revised model for the structure of the Korean mental lexicon is proposed, one which accounts for cross-script semantic cohorts, allowing for a more conceptual representation of the contributions of Hanja characters in the Sino-Korean lexicon.