Integrating and Comparing Frequency Data and Basic Word Lists for Establishing Vocabulary Allocation by School Year in Primary and Secondary Education

Abstract

In Japanese language education, the school-year-based allocation of kanji is often emphasized, yet words represent more fundamental learning units. This study aims to develop and propose year-level word lists for primary and secondary education. To this end, we compiled word frequency data from children’s corpora—textbooks, children's newspapers, and juvenile literature—and integrated them with entries from existing educational word lists (Tanaka 1956; Ikehara 1957; Sakamoto 1958, 1984; Jigenken 1962; Central Educational Research Institute 1984; Hamamoto 1990), standardised into UniDic short-unit forms. Frequency levels were analyzed, and weighted baseline frequencies were calculated using data from multiple corpora. The frequency distributions by assigned to each year level in each word list were then examined using medians, quartiles, and boxplots. Results showed that words for Years 1–2 appeared at high frequency levels, those for secondary at low levels, while words for Years 3–6 showed no clear frequency differences. Based on these findings, we discuss principles for allocating vocabulary by year.