Complex meanings shape early noun and verb vocabulary structure and learning.

Verbs and nouns vary in many ways-including in how they are used in language and in the timing of their early learning. We compare the distribution of semantic features that comprise early acquired verb and noun meanings and measure their effect on learning. First, couched in prior literature, we use semantic feature data to establish that features pattern on a hierarchy of complexity, with perceptual features being less complex than other features like encyclopaedic features. Second, given overall semantic and syntactic differences between nouns and verbs, we hypothesize that the preference for directly perceptible features observed for nouns will be attenuated for verbs. Building on prior work using semantic features and semantic networks in nouns, we find that compared to early learned nouns (N = 359), early learned verbs (N = 103) have meanings disproportionately built from complex information inaccessible to the senses. Third, we find that 16- to 30-month-old children's early noun and verb vocabularies (N = 3,804) show semantic relationships that differ in their use of this complex information from the beginning of vocabulary development. Last, we find that the complexity of nouns' and verbs' meanings affects their typical order of learning in early vocabulary development. Complexity differs in early noun and verb meanings, affects the semantic structure of children's vocabularies, and shapes the course of word learning. (PsycInfo Database Record (c) 2025 APA, all rights reserved).