The is a history, written in
Classical Chinese, of the Korean
Three Kingdoms period, which ended in 668. Chapter 37 gives place names and meanings, mostly for places in the
Goguryeo lands seized by
Silla. These glosses were first studied by
Naitō Torajirō in 1907, with substantial analysis beginning with a series of articles by
Ki-Moon Lee in the 1960s. For example, the following entry refers to the city now known as
Suwon: That is, the characters are used to record the sound of the name, while the characters represent its meaning. From this, it can be inferred that 買 and 忽 represent the pronunciations of local words for 'water' and 'city' respectively. In this way, a vocabulary of 80 to 100 words has been extracted from these place names. Characters like and presumably represented pronunciations based on some local version of the Chinese reading tradition, but there is no agreement on what this sounded like. One approximation is to use the
Middle Chinese reading pronunciations recorded in such dictionaries as the
Qieyun (compiled in 601), in which is pronounced . Another uses the
Sino-Korean readings of 15th century dictionaries of
Middle Korean, yielding a pronunciation of for the same character. In some cases, the same word is represented by several characters with similar pronunciations. Several of the words extracted from these names resemble Korean or
Tungusic languages. Others, including all four of the attested numerals, resemble
Japonic languages, and are accepted by most authors as evidence that now-extinct relatives of Japonic were once spoken on the Korean peninsula. The first authors to study these words assumed that, because these place names came from the territory of Goguryeo, they must have represented the language of that state. Lee and Ramsey offer the additional argument that the dual use of Chinese characters to represent the sound and meaning of the place names must have been done by scribes of Goguryeo, which would have borrowed written Chinese earlier than the southern kingdoms. They argue that the Goguryeo language formed a link between Japanese, Korean and Tungusic.
Christopher I. Beckwith, applying his own Middle Chinese readings, claims that almost all of the words have Japonic cognates. He takes this as the language of Goguryeo, which he considers a relative of Japanese in a family he calls Japanese-Koguryoic. He suggests that the family was located in western Liaoning in the 4th century BC, with one group (identified with the
Yayoi culture) travelling by sea to southern Korea and Kyushu, others migrating into eastern Manchuria and northern Korea, and others by sea to the
Ryukyu Islands. In a review for
Korean Studies, Thomas Pellard criticizes Beckwith's linguistic analysis for the
ad hoc nature of his Chinese reconstructions, for his handling of Japonic material and for hasty rejection of possible cognates in other languages. Another review by historian Mark Byington casts doubt on Beckwith's interpretation of the documentary references on which his migration theory is based. Other authors point out that none of the placenames with proposed Japonic cognates are located in the historical homeland of Goguryeo north of the
Taedong River, and no Japonic morphemes have been identified in inscriptions from the area, such as the
Gwanggaeto Stele. The glossed place names of the
Samguk sagi generally come from central Korea, in an area captured by Goguryeo from Baekje and other states in the 5th century, and suggest that the place names reflect the languages of those states rather than that of Goguryeo. This would explain why they seem to reflect multiple language groups. Kōno Rokurō and
Kim Bang-han have argued for bilingualism in Baekje, with the placenames reflecting the language of the common people. == Other evidence ==