Within the
Ryukyu Kingdom, territory was divided into
magiri, which in turn were divided into
shima. A magiri was comparable to a
Japanese prefecture while shima were individual villages. There were about 800 shima in the Ryukyu Kingdom. Linguists Seizen Nakasone and Satoshi Nishioka have proposed that each shima developed their own distinct dialects or accents due to people very rarely traveling outside of their shima. At high level, linguists mostly agree to make the north–south division. In this framework, Northern Ryukyuan covers the
Amami Islands,
Kagoshima Prefecture and the
Okinawa Islands,
Okinawa Prefecture. The subdivision of Northern Ryukyuan, however, remains a matter of scholarly debate. In the
Okinawa-go jiten (1963),
Uemura Yukio simply left its subgroups flat: • Amami–Okinawan dialect group •
Kikai language •
Amami Ōshima language • Northern dialect •
Southern dialect •
Tokunoshima language •
Okinoerabu language • Eastern dialect • Western dialect •
Yoron language •
Northern Okinawan (Kunigami dialect) •
Southern Okinawan Several others have attempted to create intermediate groups. One of two major hypotheses divides Northern Ryukyuan into Amami and Okinawan, drawing a boundary between Amami's
Yoron Island and
Okinawa Island. The same boundary was also set by early studies including
Nakasone (1961) and
Hirayama (1964).
Nakamoto (1990) offered a detailed argument for it. He proposed the following classification. • Northern Ryukyuan dialect • Amami dialect • Northern Amami • Southern Amami • Okinawan dialect •
Northern Okinawan •
Southern Okinawan The other hypothesis, the three-subdivision hypothesis, is proposed by Uemura (1972). He first presented a flat list of dialects and then discussed possible groupings, one of which is as follows: • Amami–Okinawan dialect group • Ōshima–Tokunoshima group •
Ōshima •
Tokunoshima • Okinoerabu–Northern Okinawan group •
Okinoerabu •
Northern Okinawan •
South–Central Okinawan dialects The difference between the two hypotheses is whether Southern Amami and Northern Okinawan form a cluster. Thorpe (1983) presented a "tentative" classification similar to Uemura's: • Amami–Okinawa • North Amami •
Kikai •
North Ōshima •
South Ōshima (with Kakeroma, Yoro, Uke) •
Tokunoshima • South Amami–North Okinawa •
Okierabu •
Yoron •
North Okinawa •
Motobu Peninsula •
Ieshima •
Izena, Iheya •
Kudaka •
Central and South Okinawa • Central Okinawa • Kume, Aguni, Kerama • South Okinawa
Karimata (2000) investigated Southern Amami in detail and found inconsistency among isoglosses. Nevertheless, he favored the three-subdivision hypothesis: • Amami–Okinawan dialect group •
Amami–
Tokunoshima dialects •
Okinoerabu–
Yoron–
Northern Okinawan dialects •
South–Central Okinawan dialects The renewed classification is adopted in Heinrich et al. (2015). The membership of Kikai Island remains highly controversial. The northern three communities of Kikai Island share the seven-vowel system with Amami Ōshima and Tokunoshima while the rest is grouped with Okinoerabu and Yoron for their five-vowel systems. For this reason, Nakamoto (1990) subdivided Kikai: • Amami dialect • Northern Amami dialect • Northern Amami Ōshima • Southern Amami Ōshima • Northern Kikai • Southern Amami dialect • Southern Kikai • Okinoerabu • Yoron Based on other evidence, however, Karimata (2000) tentatively grouped Kikai dialects together. As of 2014,
Ethnologue presents another two-subdivision hypothesis: it groups Southern Amami, Northern Okinawa and Southern Okinawa to form Southern Amami–Okinawan, which is contrasted with Northern Amami–Okinawan. It also identifies Kikai as Northern Amami–Okinawan. Heinrich et al. (2015) refers to the subdivisions of Northern Ryukyuan as only "Amami" and "Okinawan". There is a note that other languages, specifically within the
Yaeyama language, should be recognized as independent due to mutual unintelligibility. ==References==