The aim in this paper is to develop a tool which extracts expressions belonging to the closed category such as 'niyotte,' 'kamoshirenai.' First, we describe the problem of NLP tools when they are applied to the Japanese language education field. Then, we discuss how to extract functional morphemes. Such methods as using simple matching and morphological analysis are examined. Finally, we make a tool which post-processes the results of the morphological analysis considering environmental conditions. The tool is designed for general purposes and can be used with ease.
