American and Japanese Listener Assessment of Japanese EFL Speech: Pronunciation Features Affecting Intelligibility

A study was conducted to examine what pronunciation aspects of Japanese EFL speakers cause mis-hearings for both American and Japanese listeners. Speech samples of 20 Japanese students were evaluated by Japanese and American judges for intelligibility and accentedness. Intelligibility was measured unambiguously by comparing what the subjects intended to say and what the judges transcribed. The judges also rated the accentedness of the subjects impressionistically on a scale of 7. Interviews were then conducted with the judges to discuss what pronunciation features were perceived to be the primary causes of their misunderstandings. Analysis of the data seems to indicate that intelligibility and accentedness have a quasi-independent relationship and that a strong accent does not necessarily lead to unintelligibility. Data also indicate that most of the pronunciation mistakes perceived to have caused misunderstandings are segmental, not suprasegmental. Few suprasegmental features were perceived to have caused problems, except for word stress irregularities which proved detrimental to intelligibility in quite a few cases.