Assessing the effects of “native speaker” status on classic findings in speech research

It is common practice in speech research to only sample participants who self-report being “native English speakers.” Although there is research on differences in language processing between native and non-native listeners (see Lecumberri et al., 2010 for a review), the majority of speech research that aims to establish general findings (e.g., testing models of spoken word recognition) only includes native speakers in their sample. Not only is the “native English speaker” criterion poorly defined, but it also excludes historically underrepresented groups from speech perception research, often without attention to whether this exclusion is likely to affect study outcomes. The purpose of this study is to empirically test whether and how using different inclusion criteria (“native English speakers” vs. “non-native English speakers”) affects several well-known phenomena in speech perception research. Five hundred participants completed word (N = 200) and sentence (N = 300) identification tasks in quiet and in moderate levels of background noise. Results indicate that multiple classic findings in speech perception research—including the effects of noise level, lexical density, and semantic context on speech intelligibility—persist regardless of “native English” speaking status. However, the magnitude of some of these effects (and the interactions among them) differed across participant groups.