Articulatory Positions Research Articles

Variations in articulatory movement with changes in speech task.

Studies of normal and disordered articulatory movement often rely on the use of short, simple speech tasks. However, the severity of speech disorders can be observed to vary markedly with task. Understanding task-related variations in articulatory kinematic behavior may allow for an improved understanding of normal and disordered speech motor behavior in varying communication contexts. This study evaluated how orofacial kinematic behavior varies as a function of speaking task in a group of 15 healthy male speakers. The speech tasks included a nonsense phrase with a high frequency of stop consonants, a sentence, an oral reading passage, and a spontaneous monologue. In addition, rate and intensity conditions were varied for the nonsense phrase and sentence. The articulatory positions of the upper lip, lower lip, tongue blade, and mandible were recorded, and measures reflecting (a). average features of individual movements or strokes (i.e., peak speed, distance, and duration) and (b). overall spatial variability of the articulators for each task were extracted, derived, and analyzed. Results showed a number of task- and condition-related differences in speech kinematic behavior. The most prominent result from the task comparison was that the nonsense speech task exhibited larger, faster, and longer movement strokes than the other speech tasks. For some articulators (lower lip and tongue), there were task-related differences in spatial variability. Changes in loudness and rate revealed variation in kinematic measures that were often complicated by articulator identity and task type. The results suggest that an expanded range of speech tasks and conditions may aid in the study of normal and disordered speech motor behavior.

A Palatographic Investigation of Place of Articulation in Korean Coronal Obstruents

Abstract. This study uses static palatography to determine articulatory positions for coronal obstruents, for five native speakers of Seoul Korean in their twenties. For four of the speakers, affricates are consistently articulated slightly further back on the teeth than stops. However, stops, affricates and fricatives all show contact patterns in the denti-alveolar region. These results may reflect a shift in place of articulation of affricates from post-alveolar to denti-alveolar, for younger speakers of Korean. Gender differences are not observed for contact patterns on the palate, but contact patterns on the tongue do vary with gender. Female speakers in this study use laminal articulations, while male speakers use apico-laminal ones. The plain-aspirated-tense distinction does not affect articulatory measures of place of articulation, or amount of tongue-palate contact, implying that the lax-aspirated-tense distinction need not necessarily involve concomitant place distinctions.

Somatosensory basis of speech production.

The hypothesis that speech goals are defined acoustically and maintained by auditory feedback is a central idea in speech production research. An alternative proposal is that speech production is organized in terms of control signals that subserve movements and associated vocal-tract configurations. Indeed, the capacity for intelligible speech by deaf speakers suggests that somatosensory inputs related to movement play a role in speech production-but studies that might have documented a somatosensory component have been equivocal. For example, mechanical perturbations that have altered somatosensory feedback have simultaneously altered acoustics. Hence, any adaptation observed under these conditions may have been a consequence of acoustic change. Here we show that somatosensory information on its own is fundamental to the achievement of speech movements. This demonstration involves a dissociation of somatosensory and auditory feedback during speech production. Over time, subjects correct for the effects of a complex mechanical load that alters jaw movements (and hence somatosensory feedback), but which has no measurable or perceptible effect on acoustic output. The findings indicate that the positions of speech articulators and associated somatosensory inputs constitute a goal of speech movements that is wholly separate from the sounds produced.

Language‐specific vocal tract configurations during nonspeech

Previous work has been found to be surprisingly low within‐speaker variability in baseline articulator positions during inter‐utterance nonspeech [Gick, Phonetica (2002)], raising the question of whether these baseline positions may in fact be active in speech production. If so, then they should be specified and should vary systematically across languages. A study was conducted to test for cross‐language differences in inter‐utterance articulator positions. Individual video frames were extracted at the midpoint of interutterance pauses in x‐ray films of 5 French and 5 English speakers. Measures were made of articulator positions relative to fixed bone points, and values normalized to jaw size. Frames with potentially confounding surrounding phonetic contexts were omitted. Results for lip measures indicate that French speakers have significantly greater protrusion of the lower lip, but significantly less upper lip protrusion, than English speakers. Additional results will be presented for lingual articulators. Thus these baseline vocal tract configurations do appear to be specified differently for different languages. Additional implications will be discussed, such as possible roles these configurations may play in phonology, potential influence on vowel systems (especially schwa), and cross‐language vowel normalization. [Research supported by NSERC and NIH.]

Text-to-speech from concatenation of articulatory units derived from natural speech

It has been conjectured that articulatory synthesis possesses the greatest potential for generating high quality synthetic speech. However, for text-to-speech (TTS), waveform concatenation techniques have proven more practical due in part to the challenge of generating appropriate trajectories of articulatory parameters. A waveform generation method for TTS that combines the practical success of concatenative methods with the quality potential of articulatory synthesis is under development. The system concatenates articulatory units derived from natural speech using an articulatory voice mimic. The mimic estimates articulatory parameters by minimizing a cost function that includes a spectral distance between natural and synthetic speech and a geometric distance that penalizes rapid or discontinuous changes in articulator positions. A database of articulatory trajectories representing phonetic units is constructed from the estimated parameters. For TTS, phonetic units generated by text analysis are used to select the corresponding articulatory units from the database. Duration modification, concatenation, and smoothing across units are performed in the articulatory domain resulting in a single articulatory trajectory for the complete utterance. Speech is synthesized from the trajectory using a two mass model for voicing, achieving a high degree of acoustic continuity across unit boundaries while also allowing for source–tract interaction.

Time-varying acoustic and articulatory characteristics of American English [ɹ]: a cross-speaker study

The present study is an attempt to discover time-varying acoustic correlates of articulatory movements of American English [ɹ] using the X-ray microbeam speech production database. American English [ɹ] is known to be variable in its articulatory postures, whereas a single acoustic correlate—a low third formant—is associated with the sound. A previous study (Westbury, Hashi, & Lindstrom (1998), Speech Communication 26, 203–226) found no relation between articulatory postures and formant frequencies at phonation onset of words beginning with the sound. The present study examined acoustic–articulatory relations in time-varying acoustic and articulatory characteristics in the transition from [ɹ] to a following low- or mid-back vowel. In intervals involving a major F3 rise, a relatively strong correlation ( r⩾0.7) was observed between the average rate of change in F3 (F3 slope) and the speed of the tongue pellet closest to the palate at the onset of the major F3 rise. Results from the study are discussed with respect to the acoustic theory of speech production.

Perceptual evaluation of speech and velopharyngeal function in children with and without cleft palate and the relationship to nasal airflow patterns.

The aim was to study the relationship between perceptual evaluation of speech variables related to velopharyngeal function and the pattern of nasal airflow during the velopharyngeal closing phase in speech in children with and without cleft palate. Fourteen children with cleft lip and palate or cleft palate only and 15 controls aged 7 and 10 years. All were native Swedish speakers. Three experienced listeners performed a blinded perceptual speech evaluation. Nasal airflow was transduced with a pneumotachograph attached to a nasal mask. The duration from peak to 5% nasal airflow, maximum flow declination rate, and nasal airflow at selected points in time during the transition from nasal to stop consonants in bilabial and velar articulatory positions in sentences were estimated. The analysis was focused on the perceptual ratings of "velopharyngeal function" and "hypernasality." A strong association was found between ratings of "velopharyngeal function" and "hypernasality" and the pattern of nasal airflow during the bilabial nasal-to-stop combination /mp/. Both the sensitivity and specificity were 1.00 for the bilabial temporal airflow measure in relation to ratings of "velopharyngeal function." The nasal airflow rate during /p/ in /mp/ had a sensitivity of 1.00 and specificity of 0.92 to 0.96 in relation to ratings of "hypernasality." Assessment of the nasal airflow dynamics during the velopharyngeal closing phase in speech presents quantitative, objective data that appear to distinguish between perceptually normal and deviant velopharyngeal function with high sensitivity and specificity.

Dynamic articulatory model based on multidimensional invariant-feature task representation.

A dynamic model of articulatory movements is introduced. The research presented herein focuses on the method of representing the phonemic tasks, i.e., phoneme-specific articulatory targets. Phonemic tasks in our model are formally defined using invariant features of articulatory posture. The invariant features used in the model are characterized by the linear transformation of articulatory variables and found using a statistical analysis of measured articulatory movements, in which the articulatory features with minimum variability are taken to be the invariant features. Articulatory movements making vocal-tract constrictions or relative movements among articulators reflecting task-sharing structures are typical examples of the features found to have low variability. In the trajectory formation of articulatory movements, the dimension number of the phonemic task is set at a smaller value than that of articulatory variables. Consequently, the kinematic states of the articulators are partly constrained at given time instants by a sequence of phonemic tasks, and there remain unconstrained degrees of freedom of articulatory variables. Articulatory movements are determined so that they simultaneously satisfy given phonemic tasks and dynamic smoothness constraints. The dynamic smoothness constraints coupled with the underspecified phonemic targets allow our model to explain contextual articulatory variability using context-independent phonemic tasks. Finally, the capability of the model for predicting actual articulatory movements is quantitatively investigated using empirical articulatory data.

Nasal Airflow Patterns During the Velopharyngeal Closing Phase in Speech in Children With and Without Cleft Palate

Abstract Objectives: (1) To study the nasal airflow patterns during the velopharyngeal closing phase in speech produced by children with and without cleft palate. (2) To compare the nasal airflow patterns in bilabial, dental, and velar articulation in these children. Design: Prospective, cross-sectional study of a consecutive series of children with cleft palate referred for routine speech evaluation and controls. Setting: Sahlgrenska University Hospital, Goteborg, Sweden. Participants: Seventeen children with cleft lip and palate or cleft palate only and 22 controls aged 7 and 10 years. Method: Nasal airflow was transduced with a pneumotachograph attached to a nose mask and registered together with the acoustic speech signal. Sentences containing nasal-to-stop combinations in bilabial, dental, and velar articulatory positions were used. Main Outcomes Measures: The duration from peak to 5% nasal airflow, the maximum flow declination rate, and the nasal airflow at selected points in time during the transit...

Nasal airflow patterns during the velopharyngeal closing phase in speech in children with and without cleft palate.

(1) To study the nasal airflow patterns during the velopharyngeal closing phase in speech produced by children with and without cleft palate. (2) To compare the nasal airflow patterns in bilabial, dental, and velar articulation in these children. Prospective, cross-sectional study of a consecutive series of children with cleft palate referred for routine speech evaluation and controls. Sahlgrenska University Hospital, Göteborg, Sweden. Seventeen children with cleft lip and palate or cleft palate only and 22 controls aged 7 and 10 years. Nasal airflow was transduced with a pneumotachograph attached to a nose mask and registered together with the acoustic speech signal. Sentences containing nasal-to-stop combinations in bilabial, dental, and velar articulatory positions were used. The duration from peak to 5% nasal airflow, the maximum flow declination rate, and the nasal airflow at selected points in time during the transition from nasal-to-stop consonants. In the cleft palate group, duration from peak to 5% nasal airflow was clearly longer than among the controls (p <.0001). The declination of airflow was slower (p <.006) and the rate of nasal airflow at the release of the stop consonant was higher (p <.004) in the cleft palate group. Differences between bilabial versus dental and velar articulation were found in the control group. Studies of the temporal and dynamic characteristics of the nasal airflow variations during speech appear potentially useful for the assessment of velopharyngeal function.

A weathervane ship under wave and current action: an experimental verification of the wave drift damping formula

In this paper, the stability of the equilibrium of a tanker, free to rotate around a vertical axis while being displaced with constant velocity in following sea, is experimentally analyzed. The configuration emulates a turret system and the only bifurcation parameter is the articulation (turret) position. The post-critical behavior depends strongly on the wave-current interaction and the experiments were used not only to display this fact but also to provide a direct verification of the wave drift damping formula derived in [J Fluid Mech 275 (1994) 147; J Fluid Mech 313 (1996) 39]. Although restricted to following sea, the experimental setup was able to evaluate the adequacy of the formula in predicting the coupled action of the lateral drift force and steady yaw moment, the two force components that apparently have not been yet subjected to any experimental investigation.

Linguistic skills at 6 1/2 years of age in children who required neonatal intensive care in 1986-1989.

Linguistic skills at 6 1/2 y of age, corrected for gestational age at birth, were examined in a cohort of 230 children who had required neonatal intensive care (NIC) in 1986-89, and in 71 fullterm neonatally healthy control children (C) matched to the NIC children born at < 32 gestational weeks. Ten linguistic areas were assessed. The 10th percentile score of the controls was identified in each linguistic area and used for comparisons. In 77.5% of the controls and 63.5% of the NIC children, no score was lower than the 10th percentile score of the controls. Scores lower than the 10th percentile score were more common in NIC children born at term or at 23-31 wk, and within this group of children those born at 23-27 wk, than in controls. In preterm children of < 32 wk the results in the linguistic areas of imitation of articulatory positions, comprehension of logical grammatical constructions, phonemes and word fluency differed from those of the matched controls, and in NIC children born at > or = 32 weeks the results for imitation of articulatory positions, articulatory patterns and sentences, auditory discrimination and word fluency were poorer than those of the controls.

How to Reduce an Unwritten Language to Writing: III. Phonetic Similarity, Suspicious Pairs, and Minimal Pairs

Phonetic analysis can be done with a short list of a few hundred words. First, carefully transcribe the list phonetically. Second, list the inventory of symbols. Third, tabulate the symbols by their articulatory position. Fourth, declare symbols in close articulatory proximity, that is, sounds of great phonetic similarity, as suspicious pairs. Finally, find two words with different meanings that are phonetically identical except for one member of a suspicious pair in each. Finding such a minimal pair implies that we have found a phoneme (writing symbol).

Linguistic skills at 6½ years of age in children who required neonatal intensive care in 1986–1989

Linguistic skills at 6½y of age, corrected for gestational age at birth, were examined in a cohort of 230 children who had required neonatal intensive care (NIC) in 1986–89, and in 71 fullterm neonatally healthy control children (C) matched to the NIC children born at &lt;32 gestational weeks. Ten linguistic areas were assessed. The 10th percentile score of the controls was identified in each linguistic area and used for comparisons. In 77.5% of the controls and 63.5% of the NIC children, no score was lower than the 10th percentile score of the controls. Scores lower than the 10th percentile score were more common in NIC children born at term or at 23–31 wk, and within this group of children those born at 23–27 wk, than in controls. Conclusion: In preterm children of &lt;32 wk the results in the linguistic areas of imitation of articulatory positions, comprehension of logical grammatical constructions, phonemes and word fluency differed from those of the matched controls, and in NIC children born at 32 weeks the results for imitation of articulatory positions, articulatory patterns and sentences, auditory discrimination and word fluency were poorer than those of the controls.

Articulatory kinematic and formant frequency changes across vocalic nuclei: Some preliminary analyses

There are few data relating changes in articulatory position to changes in vocalic formant frequencies. This kind of information is useful for speech-production theory in general and specifically in understanding the relationship in neurogenic speech disorders between movement effects and resulting speech-intelligibility deficits. The purpose of this study was therefore to assemble a fairly large kinematic/acoustic database on normal speakers, for a few words that have proven useful in our studies of the intelligibility deficit in dysarthria. Data were part of the x-ray microbeam database, and for the present study included the words ‘‘hail,’’ ‘‘shoot,’’ and ‘‘coat.’’ The position histories of four tongue pellets and two lip pellets as well as the time histories of the first and second formant frequencies were studied for 45 young adult speakers. The F2 transition extent (change in F2 across a defined time interval) was significantly correlated with some combination of the pellet time histories for each word, and the magnitude of the correlation showed clear gender effects. Results will be discussed in terms of the linkage between planar kinematic data and acoustic data in predicting speech-intelligibility deficits. [Work supported by NIH DC03723 and DC000820.]

A self-learning predictive model of articulator movements during speech production.

A model is presented which predicts the movements of flesh points on the tongue, lips, and jaw during speech production, from time-aligned phonetic strings. Starting from a database of x-ray articulator trajectories, means and variances of articulator positions and curvatures at the midpoints of phonemes are extracted from the data set. During prediction, the amount of articulatory effort required in a particular phonetic context is estimated from the relative local curvature of the articulator trajectory concerned. Correlations between position and curvature are used to directly predict variations from mean articulator positions due to coarticulatory effects. Use of the explicit coarticulation model yields a significant increase in articulatory modeling accuracy with respect to x-ray traces, as compared with the use of mean articulator positions alone.

Speech Sample Effects on Pressure and Flow Measures in Children with Normal or Abnormal Velopharyngeal Function

Abstract Objective: This study examined the effect of certain test phoneme contexts on oral pressure and nasal flow values in young children with normal velopharyngeal (VP) function. Comparison was made with responses from children with abnormal function. Speakers: Ten children judged to have normal VP function (mean age = 5.2 years) and five children with VP incompetence (mean age = 7.8 years) were evaluated. Both groups were able to produce the speech sample with standard articulatory postures. Subjects were from the local community and a university cleft palate clinic. Design: Simultaneous oral pressure and nasal flow recordings were obtained from the speakers as they produced /p/ in speech stimule that varied in terms of test phoneme position in the syllable (releasing and arresting), adjacent vowel height (high, middle, and low), or adjacent consonant characteristics (voicing, placement, and manner). Within-subject differences in pressure and flow were examined to evaluate specific stimulus contrasts...

Speech sample effects on pressure and flow measures in children with normal or abnormal velopharyngeal function.

This study examined the effect of certain test phoneme contexts on oral pressure and nasal flow values in young children with normal velopharyngeal (VP) function. Comparison was made with responses from children with abnormal function. SPEAKERS: Ten children judged to have normal VP function (mean age = 5.2 years) and five children with VP incompetence (mean age = 7.8 years) were evaluated. Both groups were able to produce the speech sample with standard articulatory postures. Subjects were from the local community and a university cleft palate clinic. Simultaneous oral pressure and nasal flow recordings were obtained from the speakers as they produced /p/ in speech stimuli that varied in terms of test phoneme position in the syllable (releasing and arresting), adjacent vowel height (high, middle, and low), or adjacent consonant characteristics (voicing, placement, and manner). Within-subject differences in pressure and flow were examined to evaluate specific stimulus contrasts in each speaker group. Data were collected in the Speech Physiology Laboratory in the Hearing and Speech Department at the University of Kansas Medical Center. There were few speech sample effects on oral pressure for children with VP competence. Nasal flow for this group occurred infrequently but was present at least once in 80% of the subjects. The speakers with VP incompetence demonstrated predictable phoneme context effects (higher flow and lower pressure for a nasal context; higher flow for a high vowel context). The finding of no significant stimulus effects for the normal speakers suggests the need for little concern when choosing stimuli for normative study of oral pressure. However, certain stimulus contexts should be considered for data collection if results are to be applied to children with abnormal velopharyngeal function.

Speech and language skills in children who required neonatal intensive care. II. Linguistic skills at 6½ years of age

Linguistic skills at 6½ y of age were examined in a cohort of 284 children requiring neonatal intensive care (NIC) and in 40 controls. Ten linguistic areas were assessed. The results are presented for gestational age groups. The 10th percentile score of the controls was identified in each linguistic area. Seventy percent of the controls and &lt;27% of the NIC children had no score lower than the 10th percentile score. Scores lower than the 10th percentile score were more common in NIC children born at term or at 23–31 wk, and within the latter group in those born at 28–31 wk, than in those born at 32–36 wk gestational age. The linguistic areas of auditory discrimination, imitation of articulatory positions and imitation of sentences were most frequently affected. NIC children born at 32–36 wk performed better in the last two areas than those born at &lt;32 wk. To be a twin and born at 28–31 wk was associated with an increased risk of having more than five scores lower than the 10th percentile score of the controls.

Speech and language skills in children who required neonatal intensive care. II. Linguistic skills at 6 1/2 years of age.

Linguistic skills at 6 1/2 y of age were examined in a cohort of 284 children requiring neonatal intensive care (NIC) and in 40 controls. Ten linguistic areas were assessed. The results are presented for gestational age groups. The 10th percentile score of the controls was identified in each linguistic area. Seventy percent of the controls and <27% of the NIC children had no score lower than the 10th percentile score. Scores lower than the 10th percentile score were more common in NIC children born at term or at 23-31 wk, and within the latter group in those born at 28-31 wk, than in those born at 32-36 wk gestational age. The linguistic areas of auditory discrimination, imitation of articulatory positions and imitation of sentences were most frequently affected. NIC children born at 32-36 wk performed better in the last two areas than those born at <32 wk. To be a twin and born at 28-31 wk was associated with an increased risk of having more than five scores lower than the 10th percentile score of the controls.