2013Evidentials in Ryukyuan: the Shuri Variety of Luchuan. A Typological and Theoretical Study of Grammatical Evidentiality. Leiden: Brill [Brill’s studies in language cognition and culture 4].
1999Okinawa-jin wa doko kara kita ka: Ryūkyū, Okinawa-jin no kigen to seiritsu (Where did the Okinawans come from? Origin and formation of the Ryukyuans/Okinawans). Naha: Bōdā Inku.
2010The historical development of Japanese tone. Part I: From proto-Japanese to the modern dialects. Part II: The introduction and adaptation of the Middle Chinese tones in Japan. Wiesbaden: Harrassowitz Verlag [Veröffentlichungen des Ostasien-Instituts der Ruhr-Universität Bochum 59].
2016Kata tane, ase, ame to iki, fune, oke, nabe ga akusento-kei de kubetsu sareru Nihongo hondō hōgen: Saga Kishima hōgen to Ryūkyū-go no hikaku (A mainland Japanese dialect where ‘shoulder’, ‘seed’, ‘sweat’, ‘rain’ are distinguished from ‘breath’, ‘boat’, ‘bucket’, ‘pot’ by accent. A comparison between the Saga Prefecture Kishima dialect and Ryukyuan). Proceedings of the 30th General Meeting of the Phonetic Society of Japan, 138–145. Tokyo: Waseda University.
1983 Kyūshū hōgen no gaisetsu (Outline of the Kyushu dialects) [Kōza hōgengaku 9 Kyūshū chihō no hōgen, Iitoyo, Kiichi et al. (eds.) 1–28], Tokyo: Kokushokankōkai,
1984Nihon-go sogo no akusento to Ryūkyū hōgen (The accent of proto-Japanese and the Ryukyu dialects), Sophia linguistica19. 3–25. Tokyo: Sophia University.
1984 Izu shotō no hōgen (Dialects of the Izu islands). [Kōza hōgengaku 5 Kantō no Hōgen, Iitoyo, Kiichi et al. (eds.) 233–271], Tokyo: Kokushokankōkai.
2009 Once again on long vowels and register in proto-Japonic. Paper presented at the workshop The history and reconstruction of Japanese accent, 3–4 September. Paris: CRLAO – CLI.
2003 When and from where did the Japonic language enter the Ryūkyūs? A critical comparison of language, archaeology and history. Nihon-go keitō-ron no genzai (Perspectives on the origins of the Japanese language), Osada, Toshiki and Vovin, Alexander (eds.), 463–475. Kyoto: International Research Center for Japanese Studies.