A comparison of sung and spoken phonation onset gestures using high-speed digital imaging.

Phonation onset is important in the maintenance of healthy vocal production for speech and singing. The purpose of this preliminary study was to examine differences in vocal fold vibratory behavior between sung and spoken phonation onset gestures. Given the greater degree of precision required for the abrupt onset sung gestures, we hypothesize that differences exist in the timing and coordination of the vocal fold adductory gesture with the onset of vocal fold vibration.

Speech motor development during acquisition of the voicing contrast.

Lip and jaw movements were studied longitudinally in 19-month-old children as they acquired the voicing contrast for /p/ and /b/. A movement tracking system obtained lip and jaw kinematics as participants produced the target utterances /papa/ and /baba/. Laryngeal adjustments were also tracked through acoustically recorded voice onset time (VOT) of the consonants.

Acoustic features of normal-hearing pre-term infant cry.

Acoustic features of expiratory cry vocalizations were studied in 125 pre-term infants prior to being discharged from a level-3 neonatal intensive care unit. The purpose was to describe various phonatory behaviors in infants in whom significant hearing loss could be ruled out. We also compared these results with normal-hearing full-term infants, and evaluated whether linkage exists among acoustic cry features and various anthropometric, diagnostic and treatment variables obtained throughout the peri- and neonatal periods.

Inverse-filtered air flow and EGG measures for sustained vowels and syllables.

The purpose of this investigation was to compare the effects of two speaking tasks on laryngeal measures obtained from inverse-filtered air flow and electroglottograph (EGG) waveforms. Flow amplitude, air flow duty cycle, EGG duty cycle, and fundamental frequency were measured for normal young and aged adults during vowel prolongation and syllable repetition. There were significant between-task differences for flow amplitude and fundamental frequency.

A comparison of selected phonatory behaviors of healthy aged and young adults.

Selected phonatory behaviors of healthy aged and young men and women were compared. Inverse-filtered air flow, electroglottograph (EGG), and intraoral air pressure signals were recorded as subjects phonated in each of four conditions: normal, soft, loud, loud/high pitched. Minimum flow offset, flow amplitude, air flow duty cycle, EGG duty cycle, estimated subglottal pressure, and fundamental frequency were derived from the recorded signals and compared among age/gender groups.

Syllable durations of preword and early word vocalizations.

The continuity in development of syllable duration patterns was examined in 7 young children as they progressed from preword to multiword periods of vocalization development. Using a combination of lexical and chronological age points, monthly vocalization samples were analyzed for bisyllable duration and final syllable lengthening. Results revealed no systematic increase or decrease in the duration of bisyllables produced by the children as a group.

Acoustic validation of phonological knowledge and its relationship to treatment.

The speech of 4 phonologically disordered children with place and voicing errors affecting initial stop consonants was described through phonological and acoustic analyses. Productions of target voiced and voiceless alveolar and velar stops were transcribed and acoustically analyzed before and after treatment that was administered on a predetermined contrast. Three of the children produced significant, although largely imperceptible, differences in VOT for a given stop when it represented different adult stops.

A comparison of intrasubject variation across sessions of three vocal frequency perturbation indices.

Within-subject variation of three vocal frequency perturbation indices was compared across multiple sessions. The magnitude of jitter factor (JF), pitch perturbation quotient (PPQ), and directional perturbation quotient (DPF) was measured every other day for 33 consecutive days for ten female and five male normal young adult speakers. Perturbation measures were calculated using a zero-crossing analysis of taped [i] and [u] productions.

Vocal fundamental frequency characteristics during the first two years of life.

Vocal fundamental frequency (Fo) characteristics were sampled for a group of seven young children. The children were followed longitudinally for a 12-month period, spanning preword, single-word, and multiword vocalizations. The Fo characteristics were analyzed with reference to chronological age, vocalization length, and lexicon size.

Acoustic observations in young children's non-cry vocalizations.

A corpus of 1200 non-cry vocalization samples produced by 14 normal children between the ages of 11-25 months was examined retrospectively. Six percent of the samples yielded instances of either harmonic doubling (HD), fundamental frequency (F0) shift, or biphonation (Bp). These spectrographic features relate to short duration changes in F0, reflecting alterations in vocal fold state characteristics.

Clinical application of two phonologically based treatment procedures.

Two phonological process-based treatment procedures were applied in an ongoing clinical program. Subjects were 4 children aged 3:1, 3:8, 4:1, and 5:1. Two subjects were assigned to a minimal pairs contrasting procedure, and 2 were assigned to a modified cycles procedure based on results of a detailed phonological analysis.

Developmental trends in vocal fundamental frequency of young children.

Fundamental frequency (F0) values are reported for 14 children between the ages of 11 and 25 months, an age period characterized by changes in physiological and linguistic development. Subjects were grouped into 3-month age intervals reflecting a continuum of physical development and were audiotape-recorded during spontaneous speech productions. Acoustic analysis of average F0 and F0 variability was performed.

A comparison of language samples elicited at home and in the clinic.

One of the most common methods of obtaining diagnostic information about a child's language production is to collect and analyze a spontaneous language sample. Usually, this sample is collected in a clinical setting by a speech-language pathologist. Because children's language production seems very sensitive to situational variables, there is some question about the representativeness of language samples obtained in clinical settings.