J Rubin-Spitz | PubMed Health

PubMed1990

Perception of terminal fall contours in speech produced by deaf persons.

Eight deaf children produced each of nine sentences. F0 measures were obtained at several locations within each utterance (starting F0, peak F0, peak F0 in the final syllable, and final F0). The relative timing of each F0 measure (ms from onset of the utterance) was also determined. In addition, several difference measures were derived. Listeners experienced with the speech of the deaf were asked to judge whether they heard a terminal fall, rise, or a flat final intonation contour in each utterance. A multiple linear regression analysis was used to determine if any combination of the acoustic measures could predict listeners' responses. The only variable that made a significant contribution to the regression function was the temporal interval between the terminal peak F0 and the final F0. That is, the more slowly the contour fell the more likely listeners were to perceive the contour as flat, regardless of the amount (in Hz or percentage F0) by which it fell. The regression equation accounted for a statistically significant but not large proportion of the total variance. This suggests that other variables, not measured in this study, play an important role in the perception of utterance final intonation contours in the speech of the deaf.

Adolescent↗

PubMed1989

Discovering phonetic coherence in acoustic patterns.

Despite spectral and temporal discontinuities in the speech signal, listeners normally report coherent phonetic patterns corresponding to the phonemes of a language that they know. What is the basis for the internal coherence of phonetic segments? According to one account, listeners achieve coherence by extracting and integrating discrete cues; according to another, coherence arises automatically from general principles of auditory form perception; according to a third, listeners perceive speech patterns as coherent because they are the acoustic consequences of coordinated articulatory gestures in a familiar language. We tested these accounts in three experiments by training listeners to hear a continuum of three-tone, modulated sine wave patterns, modeled after a minimal pair contrast between three-formant synthetic speech syllables, either as distorted speech signals carrying a phonetic contrast (speech listeners) or as distorted musical chords carrying a nonspeech auditory contrast (music listeners). The music listeners could neither integrate the sine wave patterns nor perceive their auditory coherence to arrive at consistent, categorical percepts, whereas the speech listeners judged the patterns as speech almost as reliably as the synthetic syllables on which they were modeled. The outcome is consistent with the hypothesis that listeners perceive the phonetic coherence of a speech signal by recognizing acoustic patterns that reflect the coordinated articulatory gestures from which they arose.

Adult↗