Describing the acquisition of the passive voice by a child learner of Japanese as a second language from a Processability Theory perspective

This longitudinal case study reports on the acquisition of Japanese as a second language (L2) by a child learner with English as his first language (L1) who was acquiring Japanese naturalistically. In particular this study focusses on the acquisition by the child of a non-canonical mapping structure, namely the passive voice in relation to canonical mapping structures (e.g., the active voice) within the framework of the Unmarked Alignment Hypothesis (UAH) and the Lexical Mapping Hypothesis (LMH). These hypotheses are two of the main pillars of the extended Processability Theory (PT) (Pienemann, Di Biase & Kawaguchi, 2005). When compared to a large body of studies on the L1 acquisition of the passive voice, there have been only few theoretically motivated studies on the L2 acquisition of this structure, and further no studies to date have been undertaken using L2 child informants. The results of the earlier PT-based research (e.g., Wang, 2009) found that the acquisition of the passive voice by adult L2 learners occurred later than did the active voice. The results of the current child Japanese L2 study confirmed this, supporting Kawaguchi’s (2007) claim that the learner’s choice of a syntactic structure is restricted by developmental skills in argument-function mapping as predicted by UAH and LMH. Further, the results indicate that, prior to the emergence of the passive voice, a developmental period for the child to attempt non-canonical mapping existed and that the passive verbal morphology often appeared in a non-target like way until the end of the observation period