Cross-linguistic comparison of color word learning in German and Japanese children shows universal and language-specific processes

This study examines how German- and Japanese-speaking children acquire the meanings of color words, focusing on two theoretically distinct processes: centroid mapping and boundary delineation. While previous cross-linguistic studies have typically addressed these aspects in isolation, this paper explicitly investigates both processes simultaneously, assessing language-specific and perceptual factors contributing to lexical acquisition. Using previously collected Japanese data (re-analyzed here for comparative purposes) and newly collected German data, we explore how input frequency, naming inconsistency, category size, and perceptual saliency influence these processes. Our findings show that centroid mapping in both languages is primarily shaped by input frequency, that is, children learn prototypical meanings by hearing the respective color words often. In contrast, boundary delineation is predicted by naming consistency in adult speakers, that is, children's differentiation of color categories is based on the consistency with which adults refer to the same color with the same word. The structural characteristics of each language's lexicon affect these qualitative aspects, highlighting an interplay between perceptual constraints and language-specific lexical structures. This comparative approach provides novel insights into lexical and conceptual development, contributing to broader theoretical debates on continuity and discontinuity in semantic acquisition and informing computational models of lexical development.