Okinawa prefecture: central and north Okinawa island; Ie-jima, Iheya, Izena, and 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.
Those under 20 are mainly monolingual in Japanese (1989 T. Fukuda). Mainly older adults. Also use Japanese [jpn], especially the younger generation (Wurm and Hattori 1981).