linguistic:voice_change
Historical usage

" Ryūkyū " is an exonym and is not a self-designation. The word first appeared in the Book of Sui (636). Its obscure description of Liuqiu (流求) is the source of a never-ending scholarly debate about whether the name referred to Taiwan, Okinawa or both. Nevertheless, the Book of Sui shaped perceptions of Ryūkyū for a long time. Ryūkyū was considered a land of cannibals and aroused a feeling of dread among surrounding people, from Buddhist monk Enchin who traveled to Tang China in 858 to an informant of the Hyōtō Ryūkyū-koku ki who traveled to Song China in 1243. Later, some Chinese sources used "Great Ryukyu" (Chinese: 大琉球; pinyin: Dà Liúqiú) for Okinawa and "Lesser Ryukyu" (Chinese: 小琉球; pinyin: Xiǎo Liúqiú) for Taiwan. Okinawan forms of "Ryūkyū" are Ruuchuu (ルーチュー) or Duuchuu (ドゥーチュー) in Okinawan and Ruuchuu (ルーチュー) in the Kunigami language. An Okinawan man was recorded as having referred to himself as a "Doo Choo man" during Commodore Matthew C. Perry 's visit to the Ryūkyū Kingdom in 1852.

From about 1829 until the mid-20th century, the islands' English name was spelled Luchu, Loochoo, Loo-choo, or Lewchew, all pronounced / ˈ l uː tʃ uː /. These spellings were based on the Okinawan form Ruuchuu (ルーチュー), as well as the Chinese pronunciation of the characters " 琉球 ", which in Mandarin is Liúqiú.