The Japanese and Korean vocabularies include several thousand symbolic words and they are nearly the only native vocabulary not penetrated by Sino-Japanese or Sino-Korean. Symbolic words (including onomatopoeia) are used very frequently in all levels of Japanese and Korean, from conversation to literary works of all genres. It is unusual for Indo-European languages to have symbolic words. In contrast to Indo-European languages, the usage of mimetic words is a much more distinctive feature than the usage of onomatopoeia in the Japanese and Korean language. Symbolic words are extensively utilized in both Japanese and Korean.
In this study, the comparison of symbolic words between Japanese and Korean in both synchronic and diachronic views shows that the two languages are closely related on the basis of word-formation and the origin of symbolic words. In this thesis, I comparatively analyze the symbolic words in word-form as a starting point to verify the kinship between the two languages. Additionally, studies of historical, phonological and etymological approaches in Japanese and Korean symbolic words are comparatively discussed. This study contributes to the understanding of the close relationship between the two languages.