They are spoken on the Sakishima Islands in Okinawa Prefecture.
While the majority of Ryukyuan languages have used Chinese or Japanese script for writing, the Yaeyama Islands never had a full-featured writing system.
Islanders developed the Kaidā glyphs as a simple method to record family names, items, and numerals to aid in tax accounting.
This system was used until the 19th century introduction of Japanese-language education.
[4] Proto-Sakishima, the proto-language ancestral to the Southern Ryukyuan languages, has been reconstructed by Bentley (2008).