On the word ookame 'wolf'

Although geolinguistics in the Japanese archipelago developed significantly during the 20th century, it has historically lacked integration with comparative linguistics. This paper bridges this methodological gap by proposing a purely phonological hypothesis that reinterprets the geographical distribution of the word ookame (‘wolf’). While the Old Japanese form is *opo(₂)kami₂, the form ookame has often been treated as a sporadic change or ‘apophony’. However, we argue that it should be viewed as a regular reflex. This form was widely prevalent in the central language until the modern era, and is still attested across the archipelago today, as evidenced by historical documents, surviving toponyms, and contemporary attestations. We hypothesize that this form was originally borrowed into the central language from ancient sister languages. Building upon the Proto-Japonesian (PJ) six-vowel hypothesis and the reconstructed diphthong *oi, we analyze vowel fusion processes. We deduce the existence of a typological category of hypothetical “†kame languages,” where the proto-form *kamoi regularly changed to †kame by preserving the mid-vowel feature. Because the word for ‘wolf’ was not surveyed in the Linguistic Atlas of Japan, we instead analyze the geographical distribution of words for ‘thunder’. These words frequently incorporate a morpheme cognate with the latter element of the word for ‘wolf’, which serves as an effective heuristic to trace this phonological shift. Our analysis reveals that compounds containing kame (e.g., kamenari, dondorogame) form scattered linguistic islands, predominantly in port towns and peripheral regions around the Seto Inland Sea and northern Kansai. This suggests these †kame languages were once spoken widely before being displaced by the central language. Ultimately, this study heuristically estimates ancient isoglosses of the change PJ *oi > *e, demonstrating that reinterpreting linguistic geography through strict sound laws can effectively pinpoint unknown conservative language varieties from a vast expanse of geographical linguistic data.