Mapping the perceptual space defined by transition onset frequencies of synthetic CV stimuli

Abstract

The perception of formant transition cues to place of articulation was investigated through the use of synthetic stop-vowel stimuli. Three sets of stop-vowel stimuli were synthesized. In each set, the F2 and F3 onset frequencies were varied in an orthogonal design resulting in 110 combinations. The sets differed in the F2 and F3 transition offset frequencies which were set to be appropriate for the vowels [i, u, a]. Twenty normal-hearing listeners identified each stimulus as beginning with [b], [d] or [g]. Listeners were also asked to rate the certainty of their responses on a scale of 1 (least certain) to 5 (most certain). While resembling stop-vowel sequences, no burst or aspiration parameters were included, thus forcing listeners to use only transition information as the primary cue to place of articulation. Perceptual spaces were constructed as defined by the F2 and F3 onset frequencies. In each perceptual space each F2/F3 onset combination was assigned the phonetic code [b], [d], or [g], reflecting the plurality of subjects’ responses with certainty ratings higher than 3. The resulting spaces will be discussed in terms of the effect of the target vowel on the perception of F2 and F3 transitions.