Based on the descriptive studies of some 3-patterned and 2-patterned accentual systems in Northern Ryukyuan (Amami-Okinawa region), this research report proposes a list of vocabulary classified according to groups of accentual or tonal patterns which are supposed to exist for nouns, verbs, and adjectives in Proto-Ryukyuan. The list contains the vocabulary belonging to A, B, and C categories for nouns, and A and B categories for verbs and adjectives. Labelling these categories as "Keiretsu (categories)" and the vocabulary list as "Keiretsu-betsu goi," the paper argues that the vocabulary list will be useful in future field research on synchronic as well as diachronic studies on accent and phonology of the Ryukyuan linguistic systems.
