In this paper, the difference of “KAIZEN” and “KAIRYO” is analyzed by adopting the method of synonymous description based on the analysis of word usage. Especially, we compared the use of “KAIZEN” and “KAIRYO”, and difference of meaning on the basis of frequency, register and stylistic features, and the tendency of collocation.
First, the remarkable frequency difference of the synonyms suggests the generality and standardity of high frequency words. In the case of “KAIZEN” and “KAIRYO”, “KAIZEN” which is used more than three times based on the total frequency is more standard word than “KAIRYO”. Second, “KAIZEN” and “KAIRYO” are mostly used in public scenes and formal written style, but they are not used well in everyday scenes and comfortable conversation. In public scenes and literary works, “KAIZEN” is used more often than “KAIRYO”. Third, we analyzed whether there are any semantic differences between the subjects of “KAIRYO”, “KAIZEN”. In the case of “KAIRYO”, ①the management, ②the daily life, the health, the environment, ③the structure and the system, and ④the meaning field such as the situation, condition and relationship. On the other hand, in the case of “KAIZEN”, meaning fields such as ①civil engineering work, architecture, ②enrichment industry, ③management tend to be targeted.
In the Japanese language class, “KAIRYO” with high standard level should be taught and learned firstly, and compared with “KAIZEN” in accordance with the increase of the learning level in the future. At this time, concrete and effective guidance on vocabulary grammatical collocation should be made along with the specific use area centered on the official scene of “KAIZEN” and “KAIRYO” and the formalized writing.