The Northern Ryukyuan languages are a group of languages spoken in the Amami Islands, Kagoshima Prefecture and the Okinawa Islands, Okinawa Prefecture of southwestern Japan. It is one of two primary branches of the Ryukyuan languages, which are then part of the Japonic languages. The subdivisions of Northern Ryukyuan are a matter of scholarly debate.
Internal classification
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
Karimata (2000)'s proposal is based mostly on phonetic grounds. Standard Japanese /e/ corresponds to /ɨ/ in Northern Amami while it was merged into /i/ in Southern Amami and Okinawan.
Word-initial changed to before certain vowels in Southern Amami and several Northern Okinawan dialects while Northern Amami has . The boundary between Northern and Southern Amami is clear while Southern Amami and Northern Okinawan have no clear isogloss.
The pan-Japonic shift of can be observed at various stages in Amami–Okinawan. Unlike Northern Amami and Southern Okinawan, Southern Amami and Northern Okinawan tend to maintain labiality, though the degree of preservation varies considerably.
These shared features appear to support the three-subdivision hypothesis. However, Karimata also pointed out several features that group Northern and Southern Amami together. In Amami, word-medial changed to /h/ or even dropped entirely when it was surrounded by /a/, /e/ or /o/. This can rarely be observed in Okinawan dialects. Japanese corresponds to in Amami and in Okinawan. Uemura (1972) also argued that if the purpose of classification was not of phylogeny, the two-subdivision hypothesis of Amami and Okinawan was also acceptable.