Relative roles of three suprasegmental parameters in perceived degrees of foreign accent in Japanese

This study examined perceived degrees of foreign accent using speech of second language learners and native speakers morphed to each other in terms of three suprasegmental parameters. Results indicated that duration and f0, but not intensity, are central to accuracy and accentedness of a simple Japanese sentence. The effects of these two parameters still existed even when we evaluate only ‘accurate’ utterances. Analysis on individual learners suggested that the relative roles of duration and f0 depended on the state of the learners original utterances. The learners’ stimuli modified and matched to the three parameters of native speakers were still rated as more accented than the original native stimuli. In addition, the native stimuli matched to all of the learners’ acoustic parameters were still rated as less accented than the original learners’ stimuli. These results indicate that segmental aspects of learners’ speech significantly contribute to perceived accent as well.