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F Bell-Berti

Publications and source records attributed to F Bell-Berti.

13 recordsLinked to original sources
PubMed1991

Anticipatory velar lowering: a coproduction account.

Feature spreading and coproduction models make fundamentally different assumptions about the nature and organization of speech motor control, and yet each model is supported by some, but not all, of the existing empirical data. This has led some researchers to conclude that speakers probably use alternative strategies at different times. This study suggests that the identification of coarticulatory influences requires the concurrent identification of intrinsic articulatory characteristics of the segment. Moreover, the evidence for feature spreading or variable coarticulation strategies derives from the misidentification of such intrinsic characteristics as context effects. This velar coarticulation study used a controlled comparison between CVnN and CVnC minimal pairs, where C is an oral consonant, Vn is any number of vowels, and N is a nasal consonant. Vocalic string duration was manipulated by varying the number of segments and speech rate, allowing us to alter the time between the onsets of vocalic and subsequent consonantal gestures. Velar lowering occurred in CVn sequences, whether or not a nasal consonant followed, and similar vocalic gestures were observed across minimally contrastive environments with and without the nasal consonant. Moreover, velar lowering for the nasal consonant began in close temporal proximity to the nasal murmur. These results strongly support the coproduction model and provide insight into previously conflicting reports.

Humans↗
PubMed1989

Determining the extent of coarticulation: effects of experimental design.

The purpose of this letter is to explore some reasons for what appear to be conflicting reports regarding the nature and extent of anticipatory coarticulation, in general, and anticipatory lip rounding, in particular. Analyses of labial electromyographic and kinematic data using a minimal-pair paradigm allowed for the differentiation of consonantal and vocalic effects, supporting a frame versus a feature-spreading model of coarticulation. It is believed that the apparent conflicts of previous studies of anticipatory coarticulation might be resolved if experimental design made more use of contrastive minimal pairs and relied less on assumptions about feature specifications of phones.

Electromyography↗
PubMed1987

Palatoglossus activity during nasal/nonnasal vowels of Hindi.

Prior electromyographic (EMG) research reveals a lack of agreement as to the role of the palatoglossus muscle in speech. Some reports have concluded that it bears primary responsibility for lowering the velum and that it actively controls velar lowering on nasal sounds in speech, whereas others have concluded that it acts to assist in the tongue-body movements associated with the production of back vowels and linguavelar articulations. To clarify these conflicting claims, EMG recordings were obtained from the palatoglossus (as well as the levator palatini) muscle of a native speaker of Hindi who produced CVC nonsense and meaningful syllables containing a nasal or nonnasal vowel in a symmetric consonantal environment. The results showed the following: Palatoglossus activity for the central and back nasal and nonnasal vowels was moderately to considerably higher than for the front nasal and nonnasal vowels. The levels of palatoglossus activity for the back rounded nasal vowels and for the front nasal vowel /e/ were comparable to those for the corresponding nonnasal vowels, while in all other vowels, the nasal vowels exhibited relatively higher levels of palatoglossus activity than their nonnasal counterparts. In all nonnasal vowels, the increase in palatoglossus activity occurred simultaneously with strong levator palatini activity. On the other hand, in nasal vowels, the increase in palatoglossus activity and the decrease in levator palatini activity were virtually synchronous for the front nasal vowels, while the increase in palatoglossus activity began much earlier than the decline in levator palatini activity for the central and back nasal vowels. This difference in temporal relationship between palatoglossus activation and levator suppression for different vowel types is important since it unambiguously supports the 'gate-pull' model (that is, active velar lowering) for the production of front nasal vowels whereas in the case of central and back vowels, nasal and nonnasal, the palatoglossus appears to be primarily involved in moving the tongue-body.

Electromyography↗
PubMed1987

The Velotrace: a device for monitoring velar position.

This paper describes the Velotrace, a mechanical device designed to allow the collection of analog data on velar position. The device consists of two levers connected through a push rod and carried on a pair of thin supports rods. The device is positioned in the nasal passage with the internal lever resting on the nasal surface of the velum and the external lever positioned outside the nose. The movements of the external lever reflect the movement of the internal lever as it follows velar movement and are recorded as an analog signal using an optoelectronic position-sensing system. Results of evaluation studies indicate that the Velotrace accurately reflects the relatively rapid movements of the velum during speech.

Cineradiography↗
PubMed1982

Temporal patterns of coarticulation: lip rounding.

According to some theories, anticipatory coarticulation occurs when phones for which a feature is unspecified precede one for which the feature is specified, with consequent migration of the feature value to the antecedent phones. Carryover coarticulation, on the other hand, is often attributed to "articulatory sluggishness." In this paper, EMG evidence is provided that this formulation is inadequate, since the beginning of EMG activity associated with vowel lip rounding is independent of measures of the acoustic duration of adjacent lingual consonants. We suggest that the vowel-rounding gesture simply co-occurs during predictable intervals with portions of preceding and following lingual consonant articulations.

Acoustics↗
PubMed1981

A temporal model of speech production.

Existing models of speech production and coarticulation have failed to account for observations of real speech because they have considered timing to be a by-product of articulatory events instead of an integral organizing parameter of the speech motor plan. The model offered here considers time and timing relationships to be intrinsic to speech motor organization and the units of speech to be inherently dynamic gestures rather than static vocal tract configurations or invariant commands to the articulators.

Electromyography↗
PubMed1979

Anticipatory coarticulation: some implications from a study of lip rounding.

The anticipation of articulatory features, in particular lip rounding in anticipation of a rounded vowel, has been reported to occur as many as four segments before the segment for which the feature is specified. In the data presented here, we find that the moter commands for the rounding gesture for /u/ begin a fixed time before the onset of the vowel. This timing is unaffected by the number of consonant segments in the preceding string. Thus, the initiation of lip rounding appears to be linked to other features of the vowel articulation.

Electromyography↗
PubMed1979

Some relationships between speech production and perception.

EMG studies of the American English vowel pairs /i-I/ and /e-epsilon/ reveal two different production strategies: some speakers appear to differentiate the members of each pair primarily on the basis to tongue height; for others the basis of differentiation appears to be tongue tension. There was no obvious reflection of these differences in the speech wave-forms or formant patterns of the two groups. To determine if these differences in production might correspond to differences in perception, two vowel identification tests were given to the EMG subjects. Subjects were asked to label the members of a seven-step vowel continuum, /i/ through /I/. In one condition each item had an equal probability of occurrence. The other condition was an anchoring test; the first stimulus, /i/, was heard four times as often as any other stimulus. Compared with the equal-probability test labelling boundary, the boundary in the anchoring test was displaced toward the more frequently occurring stimulus. The magnitude of the shift of the labelling boundary was greater for subjects using a production strategy based on tongue height than for subjects using tongue tension to differentiate these vowels, suggesting that the stimuli represent adjacent categories in the speakers' phonetic space for the former, but not for the latter, group.

Humans↗
PubMed1976

An electromyographic study of velopharyngeal function in speech.

Electromyographic (EMG) recordings were obtained from the levator palatini, superior pharyngeal constrictor, middle pharyngeal constrictor, palatoglossus, and palatopharyngeus muscles of three talkers of American English. Bipolar hooked-wire electrodes were used. Each subject read nonsense words composed of three vowels (/i, a, u/), six stop consonants (/p, b, t, d, k, g/), and two nasal consonants (/m, n/) to form various stop-nasal and nasal-stop contrasts. Multiple repetitions of each utterance type were recorded and subsequently processed by computer. The levator palatini was found to be the primary muscle of velopharyngeal closure for each of the subjects. The palatopharyngeus also showed consistent oralization activity for each of the subjects, although the activity of this muscle was strongly affected by vowel environment. Two subjects showed pharyngeal constrictor muscle activity related to oral articulation, but pharyngeal constrictor activity for the third subject was related to vowel quality. Nasal articulation was accomplished by suppression of oral articulation for each subject. Vowel quality affected the strength of EMG signals for lateral and posterior pharyngeal wall muscles. In those cases where activity was different for the three vowels, activity was greatest for /a/.

Electrodes↗
PubMed1975

Tongue musculature and the feature of tension in English vowels.

Electromyographic techniques were employed to discover which, if any, intrinsic and extrinsic tongue muscles displayed a difference in overall amount of activity corresponding to the traditional tense-lax distinction between members of the English vowel pairs /i-I/, /e-epsilon/, and /u-u/. Although some muscles revealed a consistent difference, most did not. Even for those muscles where a tense-lax difference was found, the data do not support the notion that tension was a necessary of sufficient differentia of production.

Action Potentials↗
PubMedDate not supplied

The syllable method: proportion of impaired syllables as an indicator of spasmodic dysphonia severity.

We have previously proposed the 'mora method' to evaluate the degree of impairment in spasmodic dysphonia (SD) in Japanese-speaking patients. With this method, impairment is judged as the proportion of impaired morae in a 25-mora sentence in a longer passage read aloud. As the mora is the phonologically isochronic unit in Japanese, the proportion of impaired morae in speech can be used to represent the temporal proportion of impaired Japanese speech. This proportional measure of impairment reflects the perceived severity of the impairment, and is a more reliable measure than a 4-point perceptual rating scale completed either by patients or by voice professionals. In this paper, we propose a 'syllable method' to characterize the severity of impairment in English-speaking SD patients. Instead of morae, the severity of SD was represented by the proportion of impaired syllables. It should be possible to characterize SD impairments more reliably and precisely with this method than using a 4-point rating scale completed by voice professionals. Ultimately, the syllable method should become a simple and effective method for evaluating the severity of SD. Furthermore, such methods can be applied to other languages, using the appropriate phonological unit (either mora or syllable).

Adult↗