Word identification difficulties in early childhood: The role of Japanese Phonemic contrasts

This study investigated how children learning Japanese utilize vowel length and pitch accent—both phonemic contrasts in Japanese—for word pair identification. Seven word pairs were used, differing in second-mora consonant and pitch accent (ˈumi [sea] vs uˈshi [cow]), second-mora consonant (iˈnu [dog] vs iˈsu [chair]), vowel length (ˈchizu [map] vs ˈchi:zu [cheese]; ˈbiru [building] vs ˈbi:ru [beer]), word-level pitch accent (ˈame [rain] vs aˈme [candy]; ˈhashi [chopsticks] vs haˈshi [bridge]), and particle pitch accent (haˈna+ˈwa [nose + particle] vs haˈna + wa [flower + particle]). Experiment 1 tested preschoolers (ages 3, 4, and 5) and first and second graders (n = 85). Results revealed that the particle pitch accent contrast yielded significantly lower accuracy across age groups (ps < 0.05). Experiment 2 involved six-year-old preschoolers with pervasive developmental disorders (PDD) and typically developing (TD) age- and sex-matched peers (n = 14 each). PDD children had significantly lower accuracy than TD peers on word-level pitch accent and vowel length contrasts. Particle pitch accent accuracy was the lowest in both groups (ps< 0.05). Identification of the consonantal contrasts (/ˈumi–uˈshi/ and /iˈnu–iˈsu/) was near-perfect in both experiments. These results suggest pitch accent and vowel length pose challenges in early Japanese acquisition, particularly for children with developmental disorders.