Raymond G. Daniloff

Stop‐vowel coarticulation in 3‐year‐old, 5‐year‐old, and adult speakers

The perturbation of second formant onset values in CV contexts (C=/b,d,g/) caused by the vowels /i/ and /u/ was measured in CVC tokens spoken by three 3‐year olds, 5‐year olds, and adults. These preliminary results suggest similar patterns of stop‐vowel coproduction in all three groups.

Airflow measurements: theory and utility of findings.

The biomechanical movements of vocal structures are shown to control flow of expiratory air for the production of speech sounds. Laminar and turbulent air flow are discussed as they relate to sound generation. Theoretic and therapeutic utility of air flow profiles in differentiating linguistic contrasts and vocal characteristics are discussed along with considerations of relative utility and accuracy for various flow-measuring devices and strategies.

An x‐ray microbeam study of Hindi vowel articulations

Using the x‐ray microbeam system of the University of Wisconin at Madison, articulatory movement data were recorded from pellets attached to the tongue, upper and lower lips, lower jaw, and velum while a native speaker of Hindi produced ten oral vowels contained in non‐sense words of the form bVb. The data do not support the traditional descriptions of Hindi vowels given in terms of either tongue height or vocal tract openness. For example, overall position of the tongue dorsum was higher for /e/ than /ɪ/, and similar for /ᴜ/ and /o/, and also for /ʌ/ and /ɑ/. Position of the jaw was lower for /ɔ/ than for /ɑ/. The lips were more open for /o/, /ᴜ/, and /u/ than for /ɔ/, and more open for /i/ than /ɪ/, /e/, and /ɛ/. Position of the lips for /e/ and /ɛ/ was identical. The velum showed somewhat greater elevation for /e/ than /ɪ/, and identical elevation for /ᴜ/ and /o/. The remaining relations among various structures involved in vowel production were as expected. However, overall relationships among these s...

Estimation of Formant Frequency in Synthetic Infant CV Tokens

Accuracy and reliability of formant frequency measurements were tested for a microcomputer-based protocol employing FFT power spectrum analyses of diffuse, spectrally weak infant vocalizations. CV-like signals were created through multivariate parametric synthesis which utilized a range of acoustic variations characteristic of those reported for infants. The synthetic forms were then analysed in double-blind conditions by three trained phoneticians whose task was to determine first, second and third formant frequencies at initial, medial and final locations within the tokens. Inter- and intra-judge assessments indicated very accurate and reliable estimates of first and second formant frequency, independently of the confounding factors of (a) phonetic identity (six syllables) (b) range and pattern of fundamental frequency shifts (seven levels), (c) noise variation for the voicing source (four levels of aspiration), (d) nasalization (absent or present), or interactions among these (64 total combinations). E...

Evaluation of foreign accent using synthetic speech

A meaningful sentence loaded with appropriate phonemic and syllabic forms was synthesized as a “standard” stimulus, and 15 “accented” versions of the sentence were made by manipulating the following Spanish cues singly and in combination: (1) VOT for syllable‐initial voiceless stops, (2) vowel duration, (3) F1 and F2 for full vowels, and (4) F1 and F2 plus duration for reduced vowels. Two tapes were prepared on which the 15 accented stimulus sentences were each paired with the standard sentence in two randomized sequences. Ten English speakers rated how different the accented sentence was from the standard sentence on a ten‐point scale. Statistical analysis revealed a significant difference in perceived accentedness as a function of the number of cues present and in particular, differences elicited by a shift in F1 and F2 for full vowels.

Perceptual evaluation of infant articulatory transitions

The distribution of phonemic cues contained within consonant–vowel (CV) nonreduplicated (NRB) syllables of infants ages 6 to 15 months was compared to the distribution observed in adult productions [S. Furui, J. Acoust. Soc. Am. 57, 1016–1025 (1986)] to examine the extent of coproductive overlap of infant consonant and vowel gestures. Truncated versions of infant CV syllables were presented to adult listeners for syllable identification. Perceptual critical points (truncation point at which syllable identification fell below 60% for the first time) were determined for both initial and final truncation conditions, and critical intervals were calculated. Results revealed significant differences in the temporal distribution and strength of phonemic cues within the infant NRB CV syllable. Fewer than 1/3 of the infant syllables demonstrated normal, adult‐like identification functions under both initial and final truncation conditions, and infant critical intervals were on the average 21/2 times longer than tho...

Perceptual evaluation of infant CV transitions

The transition portion of the speech signal has been identified as critical to the perception of both consonants and vowels. Furui [J. Acoust. Soc. Am. 72, 43–50 (1986)] demonstrated that, for adult speakers, a 10‐ms segment of the transition centered on the area of maximum spectral movement contained the most critical information for joint consonant and vowel perception and that a period roughly 50 ms long (including the aforementioned 10‐ms critical interval) was sufficient for CV syllable perception. An investigation of the perceptual cues contained within consonant‐vowel (CV) transitions of infants ages 6–15 months was begun. CV‐like syllables were selected from the vocalizations of two infants, a male and a female, and presented to listeners for identification. Truncated versions in which portions of the transition were systematically deleted were also presented for identification and critical intervals for the perception of consonant, vowel, and syllable were calculated and compared with those obtai...

Accuracy and reliability of formant frequency measurements in infant CV‐like utterances

The accuracy and reliability of measurements of infant formant frequencies were investigated. A total of 40 CV‐type tokens (C = labial‐ or velarlike stop closant, V = /i/‐like or /ɛ‐like vocalic segment) were selected from recordings of vocalizations of two infants, ages 2–4 months. The tokens were of good acoustic quality and were taken from recordings of postfeeding mother‐child interactions. Formant frequency measurements were made from both single FIT cross sections using a 10‐ms sampling window and averaged, time‐advanced, spectra. Time‐advanced FFTs were computed using three successive FFTs taken at 2.5‐ms rightward shifts of the 10‐ms window. Three investigators independently measured formant frequencies in all tokens. Wideband 500‐Hz spectrograms of each token were used to establish baseline values of formant frequencies for comparison with measured FFT values. Inter‐ and intraobserver reliability was also determined.

Accuracy and reliability of formant frequency measurements in synthetic infant CV syllables

An investigation of the reliability and accuracy of measurement of infant formant frequencies was conducted. Four factors known to render formant measurement difficult—pitch inflection, glottal noise, jitter, and nasalization—were incorporated into synthesized CV (C = /b,d/, V = /i,a,ɛ/) syllables appropriate to 3‐month‐olds. The syllables were of high intelligibility and quality. Three fundamental frequency contours (standard rise/fall, rising, flat), three F0 levels (325, 375, 425 Hz), four voice/noise ratios (+20, +5, 0, −15), three frequency jitter rates (250, 500, 750), and one degree of nasal coupling were used. Formant frequency measurements were made in two ways for each token: (1) as single FFT cross sections using a 10‐ms window and (2) as averaged, time‐advanced FFT spectra. In the second condition, three successive FFTs taken at 2.5‐ms rightward shifts of the 10‐ms sampling window were averaged to produce the FFT spectrum for measurement. Three observers independently measured F1, F2, and F3 a...

Stop‐vowel coarticulation in the speech of normal 3‐ and 5‐year‐olds

Three 5‐ and three 3‐year‐old children were trained to produce five repetitions of symmetrical CVC syllables; C = stop consonants, V = [i, ae, u, a] in a carrier phrase. Recordings were spectrally analyzed. Frequency measurements were normalized for determination of vowel induced shifts in consonant loci. Results will be compared with adult productions in order to display age‐linked changes in coarticulatory patterns, such as were observed by Stevens, House, and Paul (1966).