Island Languages Day is observed in the Ryukyu Islands, Japan, on September 18 every year. This annual event is dedicated to the indigenous Ryukyuan languages, which UNESCO has classified as endangered. The Ryukyuan languages, part of the Japonic language family, include Amami, Kunigami, Okinawan, Miyako, Yaeyama, and Yonaguni, and they are not mutually intelligible with Japanese or among themselves. The day was initiated by the Okinawa Prefecture government to emphasize the importance of preserving these languages and their associated cultural heritage. Most fluent speakers are from the older generation, with younger individuals predominantly speaking standard Japanese or local dialects, contributing to the classification of two Ryukyuan languages as severely endangered and four others as definitely endangered.