Formant transition duration and amplitude rise time as cues to the stop/glide distinction.

There is some disagreement in the literature about the relative contribution of formant transition duration and amplitude rise time in signalling the contrast between stops and glides. In this study, listeners identified sets of /ba/ and /wa/ stimuli in which transition duration and rise time varied orthogonally. Both variables affected labelling performance in the expected direction (i.e. the proportion of /b/ responses increased with shorter transition durations and shorter rise times). However, transition duration served as the primary cue to the stop/glide distinction, whereas rise time played a secondary, contrast-enhancing role. A qualitatively similar pattern of results was obtained when listeners made abrupt-onset/gradual-onset judgements of single sine-wave stimuli that modelled the rise times, frequency trajectories, and durations of the first formant in the /ba/-/wa/ stimuli. The similarities between the speech and non-speech conditions suggest that significant auditory commonalities underlie performance in the two cases.