In 1990, he accepted a position as an assistant professor in the Kobe University Department of Literature.
His research interests cover a wide variety of areas from classical to modern forms of Japanese, and in recent years[when?]
he has been carrying out his research while advocating for and spreading awareness of the concept of yakuwarigo ("role language").
In 2006, he was awarded the Shinmura Izuru Prize for his book Nihongo sonzai hyōgen no rekishi.
he is a trustee of the Society for Japanese Linguistics, a committee member of the Linguistic Society of Japan, director of the Association for Natural Language Processing, vice president and committee member of the Society for Japanese Grammar and a member of the Science Council of Japan.