One of the chief goals of most second language learners is to be understood in their second language by a wide range of interlocutors in a variety of contexts. Although a nonnative accent can sometimes interfere with this goal, prior to the publication of this study, second language researchers and teachers alike were aware that an accent itself does not necessarily act as a communicative barrier. Nonetheless, there had been very little empirical investigation of how the presence of a nonnative accent affects intelligibility, and the notions of “heavy accent” and “low intelligibility” had often been confounded. Some of the key findings of the study—that even heavily accented speech is sometimes perfectly intelligible and that prosodic errors appear to be a more potent force in the loss of intelligibility than phonetic errors—added support to some common, but weakly substantiated beliefs. The study also provided a framework for a program of research to evaluate the ways in which such factors as intelligibility and comprehensibility are related to a number of other dimensions. The authors have extended and replicated the work begun in this study to include learners representing other L1 backgrounds (Cantonese, Japanese, Polish, Spanish) and different levels of learner proficiency, as well as other discourse types (Derwing & Munro, 1997; Munro & Derwing, 1995). Further support for the notion that accent itself should be regarded as a secondary concern was obtained in a study of processing difficulty (Munro & Derwing, 1995), which revealed that nonnative utterances tend to require more time to process than native-produced speech, but failed to indicate a relationship between strength of accent and processing time.

The approach to L2 speech evaluation used in this study has also proved useful in investigations of the benefits of different methods of teaching of pronunciation to ESL learners. In particular, it is now clear that learner assessments are best carried out with attention to the multidimensional nature of L2 speech, rather than with a simple focus on global accentedness. It has been shown, for instance, that some pedagogical methods may be effective in improving intelligibility while others may have an effect only on accentedness (Derwing, Munro, & Wiebe,1998).