Prosodic factors that affect the accentedness of L2 Japanese utterances: What matters most?

This study aims to identify which of two crucial prosodic factors has greatest impact on native speakers' judgement of the accentedness of second language (L2) pronunciation. Prosodic features are already known to have more impact on the accentedness of L2 learners' pronunciation than segmental features do. In this study, timing and pitch are looked at as major prosodic factors that affect native speakers' accentedness judgement of L2 pronunciation. To examine the relative importance of timing and pitch, two types of speech samples—natural speech and prosody-modified speech—were used. In two experiments, native Japanese listeners assessed the accentedness of these stimuli and the results were compared. Both experiments obtained the same result: that timing is more important than pitch in improving the perceived naturalness of L2 Japanese speech.