Robert L. Whitehead

Vibratory patterns of the vocal folds during pulse register phonation

The purpose of the present study was to investigate the vibratory patterns of the vocal folds during pulse register phonation. Glottal area-time functions were calculated from three high speed laryngeal films (4000 frames/second) obtained during phonation of the schwa vowel in pulse register by a normally hearing and speaking adult female. The results for the first film indicated that each of 35 consecutive vibratory cycles of the vocal folds consisted of a single opening/closing gesture followed by a lengthy closed phase. The analysis of the second film revealed that each of 33 consecutive vibratory cycles consisted of a double opening/closing vocal fold pattern, followed by a long closed phase. For the third film, the results indicated that each of 26 consecutive vibratory cycles of the vocal folds consisted of either a double or triple opening/closing gesture followed by a lengthy closed period. From these data, it appears that one of the physiological descriptors of pulse phonation is multiple, as well as single, vocal fold vibratory patterning.

Effect of vowel environment on fricative consonant duration in speech produced during simultaneous communication

This study investigated the effect of vowel environment on fricative consonant duration in contextual speech produced during simultaneous communication (SC). Previous studies (Schwartz, 1969) of vowel influences on consonant duration supported the notion of anticipatory scanning, in which final vowel targets influence the duration of preceding fricative consonants. Ten normal-hearing, experienced sign language users recorded palatal and alveolar fricatives produced in four vowel environments in contextual sentences under SC and speech-only (SO) conditions. Results indicated longer sentence durations for SC than for SO, and significant effects of vowel context on fricative consonant duration in contextual speech in both SC and SO conditions that revealed similar anticipatory scanning effects as seen in previous studies. These data confirm previous research indicating that the temporal alterations produced by simultaneous communication do not involve violations of the temporal rules of English speech.

Temporal characteristics of speech produced by inexperienced signers during simultaneous communication.

This study investigated temporal characteristics of speech produced during simultaneous communication (SC) by inexperienced signers. Recordings of stimulus words embedded in sentences produced with speech-only versus SC were made by 12 students during the first and last weeks of an introductory sign language course. Results indicated significant temporal differences between speech-only and SC conditions during both the first week and the last week of the class. Inexperienced signers appeared to sign between words in SC during the first week of the class, thereby extending interword intervals. At the last week of the class, they appeared to shift toward simultaneously signing while producing the words, thereby elongating segmental temporal characteristics, such as vowel duration. The specific temporal differences between SC and speech-only conditions were consistent with previous findings regarding the effect of SC on temporal characteristics of speech with experienced signers.

Voice onset time in speech produced by inexperienced signers during simultaneous communication

This study investigated sentence duration and voice onset time (VOT) of plosive consonants in words produced during simultaneous communication (SC) by inexperienced signers. Stimulus words embedded in a sentence were produced with speech only and produced with SC by 12 inexperienced sign language users during the first and last weeks of an introductory sign language course. Results indicated significant differences between the speech and SC conditions in sentence duration and VOT of initial plosives at both the beginning and the end of the class. Voiced/voiceless VOT contrasts were enhanced in SC but followed English voicing rules and varied appropriately with place of articulation. These results are consistent with previous findings regarding the influence of rate changes on the temporal fine structure of speech (Miller, 1987) and were similar to the voicing contrast results reported for clear speech by Picheny, Durlach, and Braida (1986) and for experienced signers using SC by Schiavetti, Whitehead, Metz, Whitehead, and Mignerey (1996).

Preservation of place and manner cues during simultaneous communication: a spectral moments perspective

UNLABELLED Spectral moments, which describe the distribution of frequencies in a spectrum, were used to investigate the preservation of acoustic cues to intelligibility of speech produced during simultaneous communication (SC) in relation to acoustic cues produced when speaking alone. The spectral moment data obtained from speech alone (SA) were comparable to those spectral moment data reported by Jongman, Wayland, and Wong (2000) and Nittrouer (1995). The spectral moments obtained from speech produced during SC were statistically indistinguishable from those obtained during SA, indicating no measurable degradation of obstruent spectral acoustic cues during SC. EDUCATIONAL OBJECTIVES As a result of this activity, the participant will be able to (1) describe SC; (2) explain the role of SC in communication with children who are deaf; (3) describe the first, third, and fourth spectral moments of obstruent consonants; and (4) identify spectral moment patterns in speech produced during SC.

Some spectrographic and perceptual features of vocal fry, abnormally rough and modal register vowel phonations

Abstract Twenty normal-speaking young adult males phonated (at one intensity) in modal register, with simulated abnormal vocal roughness, and in vocal fry register each of the five test vowels, /u/, /i/, /^/, /a/ and /ae/. Each test production was rated for roughness by a panel of 11 listeners; a median of the ratings for each production was then obtained. Additionally, the acoustic wave of each production was analyzed to produce a narrow-band (3 Hz) intensity-by-frequency acoustic spectrum in which multiple (25) measures of spectral noise (inharmonic component) level were obtained. For each test vowel, the median roughness ratings for fry productions were similar in magnitude to those for simulated abnormally rough productions and exceeded (P

Preservation of Second Formant Transitions during Simultaneous Communication: A Locus Equation Perspective.

UNLABELLED This study investigated the preservation of second formant transition acoustic cues to intelligibility in speech produced during simultaneous communication (SC) from a locus equation perspective. Twelve normal hearing, experienced sign language users were recorded under SC and speech alone (SA) conditions speaking a set of sentences containing monosyllabic words designed for measurement of second formant frequencies in consonant-vowel-consonant (CVC) syllables. Linear regression fits made to coordinates representing second formant transition onset and offset frequencies following stop consonant release of CVC syllables (locus equations) were used to examine place of articulation cues in both SA and SC conditions. Although results indicated longer sentence durations for SC than SA, locus equation slopes and intercepts obtained from speech produced during SC were virtually identical to those obtained during SA, indicating no degradation of stop consonant acoustic cues during SC. This conclusion is consistent with previous research indicating that temporal alterations produced by SC do not involve violations of other rules of spoken English. EDUCATIONAL OBJECTIVES As a result of this activity, the participant will be able to (1) describe SC; (2) explain the role of SC in communication with children who are deaf; (3) describe second formant transitions in English speech; and (4) identify second formant transition patterns in speech produced during SC.

Effect of vowel environment on consonant duration: an extension of normative data to adult contextual speech.

In this study, we investigated the effect of vowel environment on consonant duration in contextual speech produced by adults. Previous studies, such as Schwartzs published in 1969 and DiSimonis in 1974, of vowel influence on consonant duration have supported the notion of anticipatory scanning in which final vowel targets influence the duration of preceding fricative consonants. These studies were based on repetitions of nonsense syllables by children and adults, but no research has been reported that extends these data to contextual speech or examines speaker gender differences. Forty adult normal speakers (20 women and 20 men) recorded palatal and alveolar fricatives produced in four vowel environments in words embedded in contextual sentences. Results indicated significant effects of vowel context on consonant duration in contextual speech and revealed anticipatory scanning effects that are similar to those seen with nonsense syllables in previous studies. These normative data can form the basis for comparison of the effects of temporal alterations produced by speaking conditions such as simultaneous communication.

Effect of sign task on speech timing in simultaneous communication

The purpose of this investigation was to study the effect of the signing task on temporal features of speech during simultaneous communication (SC). The effects of three independent variables: (a) communication mode (speech only vs. SC); (b) sign task demand (base vs. elaborated signs); and (c) type of sign movement (kinetic vs. morphokinetic) were studied on five dependent variables: (a) word duration; (b) sentence duration; (c) diphthong duration; (d) interword interval before signed experimental word (IWIB); and (e) interword interval after signed experimental word (IWIA). Audio recordings were made of 12 normal hearing, experienced sign language users speaking experimental words that varied in sign task demand and movement under SC and speech only (SO) conditions. Results indicated longer sentence durations for SC than SO and longer anticipatory durations of IWIB and diphthong before signed words, especially those using signs with greater task demand or with movements including hand shape change. IWIA only lengthened for SC vs. SO with no further effect of sign task demand or movement. These results indicate finite effects of sign task demand and movement on pause and segment durations before the sign but not as strong an effect as has been reported for increased finger spelling task length.

Production and Perception of Final Consonant Voicing in Speech during Simultaneous Communication.

Simultaneous communication combines both spoken and manual modes to produce each word of an utterance. This study investigated the potential influence of alterations in the temporal structure of speech produced during simultaneous communication on the perception of final consonant voicing. Experienced signers recorded words that differed only in the voicing characteristic of the final consonant under two conditions: (a) speech alone and (b) simultaneous communication. The words were digitally edited to remove the final consonant and played to 20 listeners who, in a forced-choice paradigm, circled the word they thought they heard. Results indicated that accurate perception of final consonant voicing was not impaired by changes in the temporal structure of speech that accompany simultaneous communication.