Verbal Predicate Constructions in Japanese: The Relationship between Verb Roots and Suffixes

Abstract

This study examines the relationship between verb roots and suffixes in Japanese predicate constructions. Data are drawn from the second editions of the textbooks Minna no Nihongo Shokyū I and II. A qualitative descriptive approach is adopted, using document analysis, morpheme segmentation, and paradigmatic comparison. Data were purposively selected from verb-form summary tables and instructional sections illustrating suffix functions in context. The analysis distinguishes consonant-final and vowel-final roots, including /i/ and /e/ subtypes. The findings show that root class determines allomorph selection and morphophonemic alternations, whereas suffixes encode tense, polarity, politeness, ability, voice, volition, and interclausal relations. Suffixation can also produce new stems that serve as bases for subsequent formation. This regularity does not imply that every sequence has transparent morpheme boundaries or permits a literal translation. Constructions involving auxiliary verbs and adjective-forming suffixes require categorical distinctions. The study provides a mapping linking root classes, suffix realisations, and grammatical functions. This mapping offers a basis for teaching that explains relationships among forms while acknowledging the limitations of pedagogical data for generalisations about Japanese usage as a whole