古代日本語のワ行子音の[b]音化について--宮古・八重山方言を中心に On the Obstruentization of Old Japanese /w/ : Focusing on the Miyako and Yaeyama Dialects
琉球宮古・八重山方言では, 古代日本語のワ行子音が[b]となる顕著な音韻現象がある。これは奄美諸島の一部, 沖縄本島北端の一部の方言にもみられる。この[b]について, 従来記述的な研究報告はなされていても, その成立についての考察はほとんどなされていない。この[b]の成立は, 宮古・八重山方言においては五母音>三母音, 奄美・沖縄方言においては五母音>三母音>五母音(新[o][e]の成立に伴う)という母音変化と密接に関わっていることを明らかにした。すなわちこれらの母音変化と連動して, 古代日本語のワ行子音も宮古・八重山では[w]>[b], 奄美・沖縄では[w]>[b][gw][g]>[w]の変化を起こしていることを, [b]の音声学的特徴や琉球方言における[b]とその変種音の分布状況及び[b]のあらわれる音環境も分析しながら明らかにした。
In the Miyako and Yaeyama sub-groups of the Ryukyuan Dialects, the prominent phonological phenomenon of Old Japanese [w] becoming [b] has taken place. This is also observed in certain dialects spoken in the Amami islands and Northern Okinawa. Although there have been descriptive studies relating to this [b], to date there has been very little research into the processes involved in its formation. This paper considers this [b]-formation, analyzing the phonetic characteristics of [b], its geographical distribution, and the environments in which it occurs. It is also argued that Ryukyuan [b] is the result of the change [w]>[b] in Miyako and Yaeyama, and [w]>[b][gw][g]>[w] in Amami and Okinawa, and these changes are deeply interrelated with the vowel changes which took place in the Miyako/Yaeyama dialects (5 vowels>3 vowels) and Amami/Okinawa dialects (5 vowels>3 vowels>5 vowels (with the creation of new [e][o])). The changes of vowel systems and [w] in these dialects are summarized as follows : (1) "5 vowels>3 vowels and [w]>[b] in the Miyako/Yaeyama dialects" In the Ryukyuan dialects the 5 vowel system [i, e, a, o, u] had reduced to the 3 vowel system [i, a, u] by the end of the 15th century. This was as a result of [e] becoming [i] and [o] becoming [u]. This vowel raising and the strong exhalation which accompanied it influenced the consonants, and one result of this was that in the Miyako/Yaeyama dialects [w] became [b], and in the Yonaguni dialect [j] became [d]. (2) "5 vowels>3 vowels>5 vowels (with the creation of new [e] [o]) and [w]>[b][gw][g]>[w] in Amami/Okinawa" In certain Amami and Northern Okinawa dialects, as the vowel system reduced from 5 vowels to 3 vowels, the change [w]>[b][gw][g] was taking place. On the other hand, in the Amami/Okinawan dialect group [o] and [e] were reformed through fusion of vowel sequences, creating a new 5 vowel system. This functioned as a factor to halt the progress of the [w]>[b][gw][g] change. In the areas where [w]>[b][gw][g] had taken place, eventually the change [b][gw][g]>[w] took place due to the weakness of [b][gw][g] in Okinawa in general and the pressure of dominant [w].
国語学 55(2), 32-44, 2004-04