Acoustic correlates to the effects of talker variability on the perception of English /r/ and /l/ by Japanese listeners

It is often reported that, for non-native listeners of a language, some native speakers´ productions of non-native contrasts are easier to understand than others´. However, these effects are not well-understood, as acoustic correlates to the effects have proven difficult to establish. We report analyses of subject differences and acoustic measurements which may help to describe the acoustic phenomena underlying one class of talker effects that we have reported previously; specifically, the interaction of talker and talker condition (the number of talkers heard within a block of trials-one or several). Correlations between response measures and acoustic measures suggest that when stimuli from several talkers are mixed randomly in a block of trials, subjects without well-formed categories for /r/ and /l/ attempt to use the duration of the initial steady-state portion of an /r/ or /l/ stimulus (an unreliable cue) for categorization, whereas native speakers use F3. It also appears that they use this cue to establish criteria for “r-l” decisions, which they apply to the overall range of durations across all talkers in one block of trials