Functional segregation of segmental features, pitch-accents, and nondistinctive suprasegmental features in working memory

Abstract

Japanese has pitch-accent which contribute to lexical distinctiveness just as segmental features. A dual-task experiment was conducted to examine the independence among segmental features, pitch-accents, and nondistinctive suprasegmental features in working memory. Japanese speakers of Tokyo dialect participated in the experiment. The primary task was a working memory task which required the retention of both segmental and suprasegmental features of nonsense words. The suprasegmental features were either regular pitch-accent of Tokyo dialect or pseudopitch changes that do not exist in a Japanese accent pattern. The secondary task was silent mouthing of irrelevant verbal material either without putative pitch change, with pitch accent, or with pseudopitch change, that was performed during the retention period of the primary task. The results revealed selective interference according to distinctivity of pitch patterns in native speakers of Tokyo dialect, suggesting functional segregation between distinctive and nondistinctive suprasegmental features. In contrast, functional segregation was not observed in ‘‘non-native’’ speakers of Tokyo dialect, suggesting that the prosody of the non-native dialect acts as ‘‘second language.’’ Additionally, in both groups, suprasegmental processing did not interfere with the retention of segmental features. The results suggest that there are at least three substores for segmental features, pitch-accents, and nondistinctive suprasegmental features.