Central Okinawa, central and north Okinawa island; Iheya, Izena, Ie-jima, Sesoko islands.
Nago. Inherent intelligibility generally impossible, or very difficult, of Ryukyuan languages and Japanese [jpn]. Ryukyuan languages are 62%-70% cognate with Tokyo dialect of Japanese. Lexical similarity: Ryukyu languages: 62%–70% with Tokyo dialect of Japanese.
Mainly older adults. The younger the generation, the more fluently they speak Japanese [jpn] (Wurm and Hattori 1981). Those under 20 are mainly monolingual in Japanese (1989 T. Fukuda).