Acquisition versus long-term retention of Japanese words and syntax by children and adults: Implications for the critical period hypothesis in second language learning

The critical period hypothesis for second language learning, which states that young children learn additional languages better than adults, lacks unambiguous empirical support as well as a coherent theoretical model.;An experimental study was conducted which analyzed child-adult differences in difficulty of acquisition and long-term retention for rules of syntax and words in Japanese, a language unfamiliar to the subjects.;The results of this study found no advantage for children over adults either in acquisition or long-term memory. However, relative to the difficulty of acquisition, the children had lower forgetting rates for words than for rules when both materials were learned completely. In the lexical study, the children's performance at retention was closer to the adults' than at acquisition, whereas in the syntax study, the opposite was the case.;These results confirm the existence of developmental differences in the forgetting rates of different materials. Such results imply that, if there is an advantage for learning language at an early age, it might be localized in lexical retention.