The first experiment examined the effects of orthogonal variation in two acoustic cues that are both produced by the articulation of a stop consonant. One component of the articulation produces a temporal cue. the other a spectral cue. In a phonetic identification task. these quite different cues were found to engage in a trading relation: One cue could, within limits. substitute for the other. In a second experiment. the perceptual equivalence implied by that trading relation was put to a stricter test. If the cues are truly equivalent in perception, then they should have their effects on the same perceptual dimension. That being so, it should be possible to combine them in such a way that. working at cross purposes in the perceptual domain, they effectively cancel each other. Pairs of patterns so produced should, then, be harder to discriminate than pairs produced by either cue alone, and still harder than those produced when the (same) two cues are combined in the opposite way and so cooperate. That expectation was confirmed. We suggest that the equivalence thus demonstrated comes about because the two cues are processed by a system specialized to take account of their common origin in speech production. So interpreted, the equivalence may be viewed as an instance of distinctively phonetic perception.In speech, the many-to-one relationship between stimulus and percept has two aspects: Several phonetic contrasts can be produced by the same acoustic cue; conversely, several acoustic cues can produce the same phonetic contrast. Examining the first aspect, one finds that the effect pervades all three phonetic dimensions. Thus, with all else constant, duration of (intersyllablic) silence, for example, can cue contrasts in manner (Haskins Laboratories, Note 1; Kuipers, Note 2), voicing , and place (port, 1976). As for the other aspect, the various acoustic cues for a particular contrast can be radically different. For example, an intervocalic voicing contrast in disyllables with the trochaic stress (rapid vs. rabid) can be cued, all else constant, by the duration of the intersyllabic silence or, alternatively, by the formant transitions at the end of the first syllable and the beginning of the next (Lisker, Note 3).It is with the second aspect of the many-to-one relationship that this paper is concerned. Specifically, it examines two of the cues for the manner contrast This work was supported by NICHD Grant HDOI994. Special thanks are due to A. Quentin Summerfield for valuable suggestions, including especially one that led to the procedure used in Experiment 2. We also thank Bruno Repp and David Isenberg for helpful comments on an earlier draft of this paper. Some of the work reported here was presented at the Spring 1977 meeting of the Acoustical Society of America, Pennsylvania State University, University Park. Pennsylvania, June 6-10. 1977. H. L. Fitch is also at University of Connecticut; A. M. Liberman is also at University of Connecticut and Yale University.exemplified by the words slit and split. One cue is...

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This study examined formant, jaw and tongue dorsum measurements from X-ray microbeam recordings of American English speakers producing emphasized vs. unemphasized words containing high-front, mid-front and low vowels. For emphasized vowels, the jaw position, regardless of vowel height, was lower, while the tongue dorsum had a more extreme articulation in the direction of the phonological specification of the vowel. For emphasized low vowels, the tongue dorsum position was lower with the acoustic consequence of F1 and F2 bunched closer together. For emphasized high and mid-front vowels, the tongue was more forward with the acoustic consequence of F1 and F2 spread more apart. These findings are interpreted within acoustic models of speech production. They also provide empirical data which have application to the C/D model hypothesis that both increased lowering of jaw and enhanced tongue gesture are consequences of a magnitude increase in the syllable pulse due to emphasis.

A system for the measurement of auditory function from 8000--20 000 Hz is described. This system introduces advances in: (a) maximum power output, (b) signal fidelity, and (c) transducer characteristics. Two case studies are presented to illustrate the clinical information gained from the measurement of high-frequency auditory sensitivity, which is not readily apparent in conventional threshold assessment.

High-frequency (8 to 20 kHz) hearing sensitivity was compared in thirty-six, 20 to 29-year-old military veterans with histories of steady-state or impulsive noise exposure. Threshold shifts were prominent for the steady-state noise subjects from 13 to 20 kHz. Mean thresholds from 8 through 12 kHz were maximally 20 dB poorer than a sample of young adult normals. Audiometric configurations for this group were generally smooth and symmetrical above 8000 Hz. For the impulsive noise group, substantial shifts in sensitivity were seen from 2 to 20 kHz and the high-frequency audiometric configurations were often jagged and/or asymmetrical. The variability of subjects in this group was greater than that seen in the steady-state noise exposed sample. Several case studies are presented to illustrate these characteristics. Measurement of auditory sensitivity from 8 to 20 kHz extends the mapping of basal cochlear function, providing information which often is not predictable from conventional audiometric measurement. This additional information provides for more comprehensive inter- and intra-subject comparison of the degree and extent of threshold changes present.