抄録
This article studied Katakana words (words written in Katakana, excluding Proper noun) in a total of 85 volumes of elementary, pre-intermediate, intermediate, and advanced Japanese textbooks, in terms of appearance rate and the type of textbooks with high appearance rate. Elementary Japanese textbooks had the highest appearance rate of Katakana words, with an average 6.44% (type frequency). The appearance rate varies according to the context of the textbook. Grouping textbooks by appearance rate of Katakana words, found that textbooks composed of Japanese daily conversations, especially textbooks which are published in recent years have a high appearance rate and usage per word.
