Abstract
For this study, I analyzed two words, kakudai (expansion) and enjo (aid) among modern new Sino-Japanese words. Inferring from their frequency of appearance in magazine corpora of the Meiji and Taisho eras, they clearly came to be included in basic vocabulary. This study describes the process of the two words' inclusion into basic vocabulary and investigates what type of relationships were established between them and existing basic words. Regarding kakudai, results indicates that the word was included into basic vocabulary as new semantics were added. In conjunction with kakudai being included into basic vocabulary due to the existing words hirogaru and hirogeru becoming inclusion into basic vocabulary on account of the Genbun-itchi Movement, its similarities with these words increased, and the semantic and stylistic relationships between them were strengthened. Regarding enjo, I came to understand that the word was included into basic vocabulary as the nature of how words took a subject and object changed, the similarities of enjo with the existing word tasukeru increased, and that the stylistic relationships between them were strengthened.
