Disyllabic Utterances Research Articles

The influence of preceding speech and nonspeech contexts on Mandarin tone identification

This study examines the effect of preceding tones on tone perception within Mandarin disyllabic utterances and the underlying mechanism that causes such an effect. Listeners were presented with a series of tone targets varying perceptually from Mandarin Tone 3 to Tone 4 following Tone 1, Tone 2, or Tone 4. The results showed that the targets were more likely to be categorized as Tone 3 following the context tones with high offset f0 (Tone 1 and Tone 2) than following those with low offset f0 (Tone 4). The effect of preceding tones compensated for the acoustic consequence of coarticulation because the context tone with high offset f0 produced Tone 4-like Tone 3 variant in production, but tended to elicit Tone 3 identification of this variant in perception. Moreover, we also observed an effect of nonspeech contexts that preserved only the f0 contours of speech contexts. However, the effect of nonspeech contexts was significantly smaller than that of speech contexts, and the difference was not caused by focal attention. Our findings lend evidence to a general auditory mechanism and point to future work clarifying the factors that modulate the magnitude of perceptual context effect.

Prosodic modulation in the babble of cochlear implanted and normally hearing infants: A perceptual study using a visual analogue scale

This study investigates prosodic modulation in the spontaneous canonical babble of congenitally deaf infants with cochlear implants (CI) and normally hearing (NH) infants. Research has shown that the acoustic cues to prominence are less modulated in CI babble. However acoustic measurements of individual cues to prominence give incomplete information about prosodic modulation. In the present study, raters are asked to judge prominence since they simultaneously take into account all prosodic cues. Disyllabic utterances produced by CI and NH infants were presented to naive adult raters who had to indicate the degree and direction of prosodic modulation between syllables on a visual analogue scale. The results show that the babble of infants with CI is rated as having less prosodic modulation. Moreover, segmentally more variegated babble is rated as having more prosodic modulation. Raters do not perceive the babble to be predominantly trochaic, which indicates that the predominant stress pattern of Dutch is not yet apparent in the children’s productions.

Is prosodic production driven by lexical development? Longitudinal evidence from babble and words.

This study investigated the relation between lexical development and the production of prosodic prominence in disyllabic babble and words. Monthly recordings from nine typically developing Belgian-Dutch-speaking infants were analyzed from the onset of babbling until a cumulative vocabulary of 200 words was reached. The differentiation between the two syllables of isolated disyllabic utterances was computed for f0, intensity, and duration measurements. Results showed that the ambient trochaic pattern emerged in babble, but became enhanced in words. Words showed more prosodic differentiation in terms of f0 and intensity and a more even duration ratio. Age or vocabulary size did not predict the expansion of f0 or intensity in words, whereas vocabulary size was related to the production of more even-timed syllables. The findings are discussed in terms of lexicalist accounts of phonetic development and a potential phonetic highlighting function of first words.

Identifying underlying articulatory targets of Thai vowels from acoustic data based on an analysis-by-synthesis approach

This paper investigates the estimation of underlying articulatory targets of Thai vowels as invariant representation of vocal tract shapes by means of analysis-by-synthesis based on acoustic data. The basic idea is to simulate the process of learning speech production as a distal learning task, with acoustic signals of natural utterances in the form of Mel-frequency cepstral coefficients (MFCCs) as input, VocalTractLab - a 3D articulatory synthesizer controlled by target approximation models as the learner, and stochastic gradient descent as the target training method. To test the effectiveness of this approach, a speech corpus was designed to contain contextual variations of Thai vowels by juxtaposing nine Thai long vowels in two-syllable sequences. A speech corpus consisting of 81 disyllabic utterances was recorded from a native Thai speaker. Nine vocal tract shapes, each corresponding to a vowel, were estimated by optimizing the vocal tract shape parameters of each vowel to minimize the sum of square error of MFCCs between original and synthesized speech. The stochastic gradient descent algorithm was used to iteratively optimize the shape parameters. The optimized vocal tract shapes were then used to synthesize Thai vowels both in monosyllables and in disyllabic sequences. The results, both numerically and perceptually, indicate that this model-based analysis strategy allows us to effectively and economically estimate the vocal tract shapes to synthesize accurate Thai vowels as well as smooth formant transitions between adjacent vowels.

Tonal variations in Anong.

This study presents an acoustic analysis of Anong tones. It has three aims: (1) to present some detailed documentation of instrumental‐acoustic data on citation tones, (2) to compare the acoustic features of the citation tones with the same tones used in disyllabic utterances, and (3) to analyze tones in disyllabic utterances. Anong citation tones are characterized by three features. First, the tonal space is small. Second, onset consonant type correlates with the pitch height of the following vowel. Third, non‐modal phonation is not an acoustic cue to any of the five tones. Neither is it a contrastive property of vowels. In disyllabic utterances, the F0 shapes and heights on the first‐syllable tones can be readily related to the F0 shapes and heights in the citation forms. The F0 value of the second‐syllable tones depends on the offset value of the tone in the first syllable. However, disyllabic forms with the prefix /a31/ follow a different pattern, one in which the first‐syllable tone is raised. This pattern correlates with vowel laryngealization and vowel duration.

Cross-language comparisons of contextual variation in the production and perception of vowels

In the last two decades, a considerable amount of research has investigated second-language (L2) learners problems with perception and production of non-native vowels. Most studies have been conducted using stimuli in which the vowels are produced and presented in simple, citation-form (lists) monosyllabic or disyllabic utterances. In my laboratory, we have investigated the spectral (static/dynamic formant patterns) and temporal (syllable duration) variation in vowel productions as a function of speech-style (list/sentence utterances), speaking rate (normal/rapid), sentence focus (narrow focus/post-focus) and phonetic context (voicing/place of surrounding consonants). Data will be presented for a set of languages that include large and small vowel inventories, stress-, syllable-, and mora-timed prosody, and that vary in the phonological/phonetic function of vowel length, diphthongization, and palatalization. Results show language-specific patterns of contextual variation that affect the cross-language acoustic similarity of vowels. Research on cross-language patterns of perceived phonetic similarity by naive listeners suggests that listener’s knowledge of native language (L1) patterns of contextual variation influences their L1/L2 similarity judgments and subsequently, their discrimination of L2 contrasts. Implications of these findings for assessing L2 learners perception of vowels and for developing laboratory training procedures to improve L2 vowel perception will be discussed. [Work supported by NIDCD.]

Cross-linguistic evidence for the acquisition of accent by the onset of word use

An investigation of the acoustic correlates of stress or accent in infant vocalizations was undertaken using five English- and five French-learning participants at two developmental points, the onset of word use (10–13 months) and late in the single-word period (14–19 months). A data base of 555 disyllabic utterances (words and babble) was digitized from naturalistic recordings and quantified acoustically by indices of duration, amplitude, and fundamental frequency (F0). Cluster analysis as well as the results of perceptual judgments (i.e., both a bottom-up and a top-down approach) revealed a developmental trend toward the adult prosodic system. In addition, acoustic comparisons of French and American infants at both developmental points revealed differences in their use of amplitude, F0, and duration to accent a syllable. The differences were traceable to the adult patterns for the respective adult languages. These results suggest that infants’ perceptual attunement to prosody in the prelinguistic period manifests itself in the beginnings of adultlike production as early as the onset of word use. [Work supported in part by the UK Economic and Social Research Council.]

Acoustic and kinematic evidence for difference in language timing structure

Proposed differences in the timing organization of Italian and Finnish are examined from the perspectives of simultaneous acoustic duration and bilabial movement (selspot tracked) collected from four native speakers of each language. All utterances were disyllabic, shaped CVC(C)V for Italian and CV(V)C(C)V(V) for Finnish. Italian, generally believed to be syllable-timed, shows regular acoustic intervals between vowels implemented by shortening of the initial vowel in closed syllables. Movement data shows that shortening is achieved by early initiation of clusters and geminate consonants, truncating the initial vowel. Finnish, generally described as mora-timed, shows increments of acoustic duration of disyllabic utterances with the addition of moras, either to vowels or to medial consonants. An apparent constraint on syllable duration leads to acoustic shortening of both initial vowels and intervocalic consonants in the longest utterances. Movement data show that increases in quantity affect both medial consonant and preceding vowel portions of utterances. It is proposed that syllable-timing works directly from vowel to vowel, while mora-timing allows increase in duration of disyllabic utterances, adjusting both vowel and consonant durations to fill out or limit the possible intervals between vowels. [Work supported by NIH Grant DC 00121 to Haskins Laboratories.]

Influence of following context on perception of the voiced-voiceless distinction in syllable-final stop consonants.

This paper reports acoustic measurements and results from a series of perceptual experiments on the voiced-voiceless distinction for syllable-final stop consonants in absolute final position and in the context of a following syllable beginning with a different stop consonant. The focus is on temporal cues to the distinction, with vowel duration and silent closure duration as the primary and secondary dimensions, respectively. The main results are that adding a second syllable to a monosyllable increases the number of voiced stop consonant responses, as does shortening of the closure duration in disyllables. Both of these effects are consistent with temporal regularities in speech production: Vowel durations are shorter in the first syllable of disyllables than in monosyllables, and closure durations are shorter for voiced than for voiceless stops in disyllabic utterances of this type. While the perceptual effects thus may derive from two separate sources of tacit phonetic knowledge available to listeners, the data are also consistent with an interpretation in terms of a single effect; one of temporal proximity of following context.

Temporal models of interarticulator programming

Two basic types of explanation have been proposed for the changes in segmental timing that occur with changes in speaking rate and syllabic stress. One view is that the segmental “commands” for syllables spoken quickly and for unstressed syllables show more extensive temporal overlap than in the same syllables spoken more slowly or with greater syllabic stress (Lindblom, 1963; 0hman, 1967). An alternative view is that the temporal relationships among articulations remain constant over changes in stress and speaking rate and that the durations of the gestures themselves change (Kent and Moll, 1975; Kent and Netsell. 1971). The experiments described here were designed to explore the temporal relationships within and among articulatory events over these suprasegmental changes. Acoustic and electromyographic measures were taken of production of simple, disyllabic utterances with varying stress and speaking rate. Analysis of the muscle activity patterns supports the second view, that temporal relationships within and among articulations remain essentially constant over changes in syllabic stress and speaking rate. [Work supported by NINCDS and BRSG.]

Phonetic variation of Vietnamese tones in disyllabic utterances

The influence of a tone on the phonetic characteristics of another tone in an adjacent syllable was examined. More specifically, the influence on each of the Vietnamese six contrastive tones was analyzed from acoustic measurements made on disyllabic test utterances. The acoustic measurements of the fundamental frequencies of the tones in different tonal environments, show that the phonetic variation of the individual tones is considerable, both in contour and overall pitch height. However, since the influence of a given environment tends to be the same in degree and manner for any tone in the adjacent syllable, the basic phonetic configuration of the six tone contrast is maintained intact despite the considerable phonetic variation of the individual tones.

Coarticulation of Some Disyllabic Utterances Measured by Electromyographic Techniques

The fact that coarticulation occurs has long been known. Recent work has shown, for example, that a subsequent vowel has spectrographic effects on a preceding vowel-consonant sequence. Furthermore, at least some of these coarticulation effects may be seen in the sequence of positions assumed by the articulators, as observed in x-ray motion pictures and by articulatory position sensors. These facts, hawever, still leave open the question of the extent to which the complex gestures of speech are reorganized at the level of the muscular contractions. The present study was designed to provide information on this question by measuring the muscle-contraction patterns of various consonant-vowel sequences. [Research supported in part by the National Institute of Dental Research, National Institutes of Health, U. S. Department of Health, Education, and Welfare.]