Innovation in Japanese Vocabulary Teaching Based on Constructivist Theory: Taking Root and Affix Association as an Example

Japanese vocabulary learning often involves heavy memorization loads, rapid forgetting, and insufficient ability to apply words flexibly. Based on constructivist theory, this paper proposes a root and affix association teaching method for Japanese vocabulary instruction. The method includes three steps: guiding learners to identify structural patterns of Chinese-character roots and native Japanese affixes, establishing morphological analysis ability; connecting new vocabulary with existing knowledge structures through association training to construct a semantic vocabulary network; and designing task-based practice activities to promote active construction of a knowledge system. Sixty intermediatelevel Japanese learners are selected and divided into an experimental group and a control group, with 30 students in each group, for a 12-week teaching intervention. The results show that the experimental group achieves an average immediate vocabulary test score of 87.3, compared with 72.8 in the control group. The delayed test retention rate after four weeks is 91.2% in the experimental group and 73.5% in the control group. Vocabulary application ability in the experimental group is 23.7% higher than that in the control group. The method effectively reduces memory burden and improves long-term retention and application accuracy.