This paper explores speech factors that influence native Japanese speakers’ perceptions of “native-like” speech. The conventional criterion of “native-like” proficiency has focused on grammar or pronunciation, which researchers recognize as important. This paper challenges this top-down discussion of “native-likeness” and examines the online (while listening) and offline (after listening) perceptions of 108 native Japanese speakers who are not academic researchers in a multi-dimensional way, in order to investigate (1) what factor(s) contribute to perceptions of “native-like” speech? and (2) For linguistically lay people, what factors determine “native-like” speech?
The methods of analysis used were factor analysis and correlations. My analysis of online perceptions of “native-likeness” is consistent with prior research that highlights grammar and pronunciation as the most important and noticeable features of non-native speakers’ speech. However, my analysis of offline perceptions reveals the significance of interaction-related factors, suggesting that grammar and pronunciation are less influential on native speakers’ holistic judgment of “native-like” speech. From these results, I propose two types of unnaturalness: overt and covert, the latter of which is illustrated to have a profound effect on native speakers’ overall impressions of non-native speakers’ speech. In conclusion, this paper highlights a possible disagreement between academic and lay perspectives with implications for teaching that places more emphasis on interaction than on accuracy for L2 learners.