助詞ハとガの談話機能の発達

抄録

Japanese postpositional particles ‘wa’ and ‘ga’ have discourse function; ‘wa’ conveys old information and ‘ga’ marks new information. The purpose of this study was to examine experimentally the development of differentiated use of ‘wa’ and ‘ga’ according to the discourse function. Ninety subjects of 4, 5, 6, 8, 10, 12, 14 years old and adults made and told stories by looking at pictures in an elicited production task. Subjects at the age of 4 and 5 used only ‘ga’ regardless of context. From 6 to 12 year old subjects began to use ‘wa’ for the referent which appeared in the previous context, but not constantly. Fourteen-year-old subjects and adults systematically differentiated ‘wa’ and ‘ga’ according to the discourse function. ‘Wa’ and ‘ga’ appear in two-word utterance stage, but our study suggests that the complete acquisition of these two particles is very late.