Location Of Constriction Research Articles

Incomplete neutralization of sibilant consonants in Penang Mandarin: A palatographic case study

It has been anecdotally observed that the three-way contrasts in Standard Chinese are reduced to two-way contrasts in Penang Mandarin (PM). PM is a variety of Mandarin Chinese spoken in Penang of Malaysia, which is influenced by Penang Hokkien. This work shows that the alleged neutralization of contrasts is incomplete (10 consonants x 3 vowel contexts x 5 speakers). More specifically, alveopalatal [ɕ] may range from postalveolar zone (73.33%) to alveolar zone (26.67%), and so does retroflex [ʂ] (46.67% vs. 46.67%). [s] and [n] are apical (or [ + anterior]) coronals. The goal of this study is three-fold: (i) to describe the places of articulation of PM coronals and the patterns of ongoing sound changes, (ii) to show the neutralization of place contrasts is incomplete whereby constriction length remains distinct for these sibilant sounds, and (iii) to demonstrate different coarticulatory patterns of consonants in variant vowel contexts. The intricate division of coronal consonants does not warrant a precise constriction location on the upper palate. This PM data lend support to Ladefoged and Wu’s (1984) observation that it is not easy to pin down a clear-cut boundary between dental and alveolar stops, and between alveolar and palatoalveolar fricatives.

A magnetic resonance imaging study on the articulatory and acoustic speech parameters of Malay vowels.

The phonetic properties of six Malay vowels are investigated using magnetic resonance imaging (MRI) to visualize the vocal tract in order to obtain dynamic articulatory parameters during speech production. To resolve image blurring due to the tongue movement during the scanning process, a method based on active contour extraction is used to track tongue contours. The proposed method efficiently tracks tongue contours despite the partial blurring of MRI images. Consequently, the articulatory parameters that are effectively measured as tongue movement is observed, and the specific shape of the tongue and its position for all six uttered Malay vowels are determined.Speech rehabilitation procedure demands some kind of visual perceivable prototype of speech articulation. To investigate the validity of the measured articulatory parameters based on acoustic theory of speech production, an acoustic analysis based on the uttered vowels by subjects has been performed. As the acoustic speech and articulatory parameters of uttered speech were examined, a correlation between formant frequencies and articulatory parameters was observed. The experiments reported a positive correlation between the constriction location of the tongue body and the first formant frequency, as well as a negative correlation between the constriction location of the tongue tip and the second formant frequency. The results demonstrate that the proposed method is an effective tool for the dynamic study of speech production.

Quantifying Compressibility and Slip in Multiparticle Collision (MPC) Flow Through a Local Constriction

The flow of a compressible fluid with slip through a cylinder with an asymmetric local constriction has been considered both numerically, as well as analytically. For the numerical work, a particle-based method whose dynamics is governed by the multiparticle collision (MPC) rule has been used together with a generalized boundary condition that allows for slip at the wall. Since it is well known that an MPC system corresponds to an ideal gas and behaves like a compressible, viscous flow on average, an approximate analytical solution has been derived from the compressible Navier–Stokes equations of motion coupled to an ideal gas equation of state using the Karman–Pohlhausen method. The constriction is assumed to have a polynomial form, and the location of maximum constriction is varied throughout the constricted portion of the cylinder. Results for centerline densities and centerline velocities have been compared for various Reynolds numbers, Mach numbers, wall slip values and flow geometries.

Tongue kinematics in palate relative coordinate spaces for electro-magnetic articulography

This paper describes a method for constructing a three-dimensional model of the hard palate using electro-magnetic articulography, and defines two algorithms to derive constriction degree and constriction location values from the trajectories of tongue coils using this model. The kinematics of tongue motion that have been transformed into constriction degree and constriction location values are investigated in detail to determine whether this type of representation obeys the constraints theorized to operate over higher level motor control. Results show that palate-relative coordinate spaces decouple mechanical dependencies present in the tongue, while maintaining low-level kinematic properties. They additionally preserve the 1/3 power law for speed and curvature observed across many motor systems. Finally, it is shown that tongue movements in a palate relative coordinate space more closely correspond to their optimal, jerk-minimized trajectories. These results suggest that this type of coordinate space provides a closer match to higher level motor-planning, in line with production models that specify control units in terms of vocal tract constriction parameters.

Characterizing post-glossectomy speech using real-time magnetic resonance imaging

We investigate articulatory behavior in post-glossectomy speech using real-time magnetic resonance imaging. Our data reveal that listeners judge speech produced by partial-glossectomy patients as atypical when the surgical procedure affected the oral tongue. Speech produced by patients whose procedure affected the base of tongue, however, was judged as typical. We observe that preservation and compensation mechanisms are exhibited by the patients with atypical speech. They preserve appropriate modulation of F1 using tongue and/or jaw height despite inability to appropriately modulate F2 due to the reduced size and/or mobility of the tongue. Further, durational differences between tense and lax vowels are maintained. The preservation of these features serves as evidence in support of a framework within which individual gestural parameters are independently controlled; when achievement of a particular parameter specification (e.g., constriction location) is compromised, the remaining (e.g., constriction degree, activation duration) are unchanged. Compensatory behavior is exhibited when coronal tongue movement has been impeded and is exemplified by (i) production of labiodental stops in place of target coronal stops and laterals and (ii) forming a velar constriction to produce frication in place of the alveolar frication for /s/.

C-V coarticulation in velar plosives

We present 114 fps lingual ultrasound data of three speakers’ productions of words containing the initial velar plosive, and the following [a] and [i] vowels, in Mangetti Dune !Xung (N = 95 for [k] in the [a] context, N = 36 for [k] in the [i] context). We traced the midsaggital tongue edge at the frame just prior to the [k] release, and measured the tongue dorsum (TD) and tongue root (TR) constriction locations (CL’s). The TRCL was measured 1 cm below the [k] peak. Results show that [k] in the [i] context has a 1.1 cm further forward TDCL than [k] in the [a] context for one speaker, and 1.2 cm further forward for the second speaker. The results are similar to those found for English by Stevens and House (1963). The TRCL is retracted 0.3 cm in [k] in the [a] context compared with [k] in the [i] context for the first speaker, and 0.6 cm more retracted for the second speaker. A third speaker had a retracted TDCL and TRCL in both vowel contexts. These results confirm that [k] is less resistant to coarticulation. Results show that the tongue root is involved in dorsal-front vowel coarticulation.

On distinguishing articulatory configurations and articulatory tasks: Tamil retroflex consonants

Speech production can be described in multiple coordinate frames: articulatory configurations, gestural tasks, and acoustic patterns. Examination of the achievement of retroflex stops and liquids in Tamil suggests that we must consider separately the gestural task of apical pre-palatal constriction and the articulatory maneuver to achieve the task. The maneuver of the tongue during retroflex consonants varies across vowel contexts. Specifically, in the symmetrical intervocalic contexts between back vowels /a/ and /u/, an apical pre-palatal constriction is achieved by curling back the tongue. In the context of high front vowel /i/, a laminal pre-palatal constriction is achieved by bunching the tongue. However, the location of retroflex consonant constriction within the vocal tract is consistent across all of these vowel contexts, suggesting that the constriction task remains the same. Variation in the articulatory configuration of the retroflex in the two contexts was quantified through Gaussian curvature functions at fourteen points along the tongue, sampled at evenly spaced points throughout the vocal tract, on every other gridline of a polar-rectangular grid in every frame in each utterance. The empirical results support the notion that the articulatory configuration coordinate frame and the gestural task frame provide separate, but related, descriptions of speech production.

Gestural reorganization under rate pressure interacts with learned language-specific phonotactics

Studies of articulatory reorganization occurring under rate-driven production pressure can provide a window into speech planning. Previous work shows evidence for stable coordinative structures in speech in which VC patterns reorganize to CV, VCC to CCV, and coronal-labial to labial-coronal order. Such stable modes are argued to result from general physical-biological constraints imposed by the articulatory/auditory system. Here we examine whether stable modes can also arise from linguistic patterns learned on a language-specific basis. The case study is Georgian, which licenses complex onsets disregarding sonority, following instead a phasing pattern whereby degree of overlap varies with order of constriction location (front-to-back /pt/ sequences are more overlapped than back-to-front /tp/). We analyze preliminary data from native speakers repeating the Georgian words [pata] and [tapa] as they tracked an accelerating metronome. Results show: 1) pAta>patA>pta (stress shift followed by elision, licensed by Georgian phonotactics); 2) tApa>tAp (elision only; consistent with Georgian order constraints, not with biomechanical constraints). These patterns are contrasted with similar data from French in which elision is not observed, consistent with French phonotactics. The data thus provide an example in which language-specific structure rather than biomechanical constraints alone mediate gestural reorganization. [Work supported by Fulbright-Hays]

An electropalatography study of nasal-trill/lateral sequences in Spanish

Trills and laterals require relatively precise articulatory and aerodynamic settings that are at least partly incompatible with setting necessary to produce nasal stops. Historically, this incompatibility has often been resolved through assimilation, deletion, or epenthesis in within-word [n+r] and [n+l] clusters (e.g., Romance [nr] > [rr] or [ndr]). It is expected that similar, yet gradient effects would be observed in across-word or hetero-morphemic sequences of nasals and liquids. This study examines the production of Spanish nasal-liquid sequences using electropalatography (EPG). Linguopalatal contact data were collected from nine native speakers of Spanish (representing three dialects) producing various utterances with nasals before /r/ and /l/ (as well as before /n/). The analysis of C1 and C2 using standard EPG indices of constriction location and degree showed that nasals had a more retracted and partly deocclusivized constriction before /r/, and a lowered tongue dorsum before both /r/ and /l/. These differences, clearly reflecting anticipatory coarticulatory effects, were similar across speakers and the three dialects, which differ in the default realization of the final nasal (alveolar or velar). The findings provide evidence for articulatory incompatibility as a source of historical development of combinations of nasals and liquids.

Articulatory-acoustic relations in Cantonese vowel production

The study investigates the quantal nature of two sets of Cantonese point vowels, the long [i: u:] in CV open syllables and the medium-long [i u] in CVS closed syllables, where S = stop consonant, by determining the articulatory-acoustic relations in the production of the four Cantonese point vowels. It evaluates Stevens' quantal theory (1972, 1989) by analyzing variability in articulation and acoustics of the four Cantonese point vowels. It also tests the sensitivity of formant frequencies of these point vowels to variation in linguo-palatal constriction location and degree of constriction along the vocal tract length. The investigation obtains variations in location and degree of linguo-palatal constriction along the vocal tract length during the point vowels, using EMMA AG500, and it relates the articulatory measurements to the corresponding vowel formant frequencies. Preliminary data show that the acoustic consequences of a shift in forward or backward direction of the constriction away from the target position for the point vowels are non-linear. The results appear to support the quantal nature of vowel production (Stevens, 1972, 1989). Furthermore, similar to the findings reported in Beckman, et al. (1995) formant frequencies are relatively less sensitive to variation in constriction location than degree of constriction.

Karyological study in fifteen Leucocoryne taxa (Alliaceae)

The karyotype of fifteen Leucocoryne taxa was studied, assessing characteristics such as chromosome morphology and size, secondary constriction location, and asymmetry level. Two groups of Leucocoryne taxa were described based on chromosome number (2n = 10 and 2n = 18) and karyotype asymmetry. The haploid karyotype formula for the group 2n = 10 was 3m + 2st (or 2t), whereas for the group 2n = 18 was 7m + 2st (or 2t). Such results corroborate the karyotype descriptions previously carried out for some taxa of the genus. Leucocoryne taxa showed a high resemblance in chromosome morphology, but inter-specific differences were found in mean chromosome size. These data and previous studies based on gross chromosome morphology support Crosa’s hypothesis, which suggests that the cytotype 2n = 10 is diploid and perhaps ancestral, whereas that the cytotype 2n = 18 is tetraploid but with an additional chromosome fusion being probably a derived status.

An in vivo radiographic evaluation of the accuracy of Apex and iPex electronic Apex locators

The aim of this study was to evaluate in vivo the clinical applicability of two electronic apex locators (EALs) - Apex (Septodont) and iPex (NSK) - in different groups of human teeth by using radiography. The working lengths (WLs) of 100 root canals were determined electronically. The EAL to be used first was chosen randomly and a K-file was inserted into the root canal until the EAL display indicated the location of the apical constriction (0 mm). The K-file was fixed to the tooth and a periapical radiograph was taken using a radiographic film holder. The K-file was removed and the WL was measured. The same procedure was repeated using the other EAL. Radiographs were examined with the aid of a light-box with lens of ×4 magnification by two blinded experienced endodontists. The distance between the file tip and the root apex was recorded as follows: (A) +1 to 0 mm, (B) -0.1 to 0.5 mm, (C) -0.6 to 1 mm, (D) -1.1 to 1.5 mm, and (E) -1.6 mm or greater. For statistical purposes, these scores were divided into 2 subgroups according to the radiographic apex: acceptable (B, C, and D) and non-acceptable (A and E). Statistically significant differences were not found between the results of Apex and iPex in terms of acceptable and non-acceptable measurements (p>0.05) or in terms of the distance recorded from file tip and the radiographic apex (p>0.05). Apex and iPex EALs provided reliable measurements for WL determination for endodontic therapy.

An evaluation of the accuracy of Root ZX according to the conditions of major apical foramen

Objectives: The purpose of this study was to assess the accuracy of Root ZX (J. Morita Corp.) according to the location of major foramen and open apex. Materials and Methods: 81 mandibular premolars with mature apices were selected. After access preparation, 27 teeth were instrumented to simulate open apices. 54 teeth were classified according to location of major foramen under surgical microscope (). The file was fixed at the location of apical constriction by Root ZX using glass ionomer cement .The apical 4 mm of the apex was exposed and photo was taken and the distance from file tip to the major foramen was measured by calibrating metal ruler on graph paper. The results were statistically analyzed using ANOVA and Scheffe test at p in group I of 85.71%, in group II of 59.09%, and in group III of 33.33%. There was a statistically significant difference between group I and III (p

Statistical estimation of speech kinematics from real-time MRI data

The human speech production system can be fundamentally characterized by the kinematic relationships between low-level articulator variables and relatively high-level tasks. Such kinematics can be illuminating about many system aspects from degrees of freedom and redundancy to dynamics and even control. Since these relationships are generally complex and infeasible to express in closed form, recent work has focused on statistical methods for estimating the relevant relationships from data (Saltzman, 2006, in Dynamics of Speech Production and Perception; Lammert, 2010, Proc. INTERSPEECH). Such methods have been applied to synthetic speech data in order to evaluate their effectiveness, but they have not yet been demonstrated on real data. Here, we apply these methods to real speech data acquired from real-time magnetic resonance imaging. We extract articulator variables that are consistent with those chosen by various articulatory models, and we relate them to high-level task variables such as constriction locations and degrees and formant frequencies. This is done to facilitate an analysis of articulatory motor control during speech production. [Work supported by NIH.]

Perceptual recovery of phonetic features in blanked segments of disyllabic words

Spondees, both true disyllabic words and concatenated monosyllabic word pairs, had their middle section replaced by silence that extended from the midpoint of the first to the midpoint of the second vowel; the silence thus included the final consonant(s) of the first and the initial consonant(s) of the second syllable. These stimuli were presented to normal-hearing young listeners instructed to guess both monosyllabic half words. Input and response spondees were orthographically aligned and analyzed as confusion matrices. Articulatory gestures were estimated for each token via the Haskins Laboratories TADA articulatory synthesis. After time alignment, articulatory distances were calculated for each stimulus-response pair. In the blanked middle of the spondee, phoneme-based confusions of place-of-articulation were high (39% accuracy), while gestural distances underlying this feature (location and degree of tongue tip constriction, lip aperture, and velar constriction) were under 10%. These results suggest that acoustic traces of a significant portion of gesture trajectories underlying consonantal place-of-articulation that start before and/or terminate after the silence, are perceived by the listener. An articulatory phonology might thus be more robust to degradation. [Work supported by NSF, AFOSR, and the VA Medical Research.]

Automatic analysis of constriction location in singleton and geminate consonant articulation using real-time magnetic resonance imaging

Research on geminate consonants has attempted to establish whether the control of their articulation differs from that of corresponding singletons in temporal parameters, spatial parameters, or both. One piece of evidence supporting spatial control in Italian geminates is EPG results revealing that the location of maximal constriction (CL) of coronal geminates along the palate exhibits small differences from the CL of singletons (Payne 2005). However, our recent work investigating Italian using real-time magnetic resonance imaging (MRI) has shown that when measuring CL dynamically, the CL of singletons and geminates are identical. Dynamic CL is defined as the region of the image that exhibits maximum intensity change during constriction formation and release. These results can be reconciled with the EPG findings if we hypothesize that differences in CL at the moment of maximal constriction are due to compression effects (in the longer geminates) involving the tongue tip sliding along the palate during the closure duration. We evaluate this hypothesis by testing whether CL differences between singletons and geminates can also be found in MRI data, when CL is measured statically (region on the palate contacted in the most constricted frame) in the same utterances in which dynamic CL is invariant. [Work supported by NIH.]

Diphthong centralization and reduction in constriction degree

Diphthongs in Mexian Hakka Chinese have been divided into two categories (Cheung 2007): Endpoints of the falling (in vowel space) diphthongs have formant values equivalent to those of the monophthongal vowels, while the endpoints of the rising diphthongs generally have more centralized formants. This categorization provides a chance to test the hypothesis of Iskarous etal. (2010) that in speech production the location of constriction (CL) changes discretely in transitions between successive targets, while the degree of constriction (CD) changes continuously. We therefore hypothesize that the centralization in these diphthongs results from a reduction in CD (possibly due to undershoot) rather than CL, thus making it parallel to common consonant reduction changes in languages, such as spirantization of stops. The current study tests this hypothesis using TADA (TAsk-Dynamic) modeling, in which CD and CL in speech production can be manipulated. Diphthongs [ia], [ua], [ai], and [au] were modeled, and the preliminary results indicate that a change in target CD alone yields formant patterns that are more similar to those reported compared with a change in CL. Results of additional studies will be presented that analytically derive CD and CL in these diphthongs from new data collected from speakers of Hakka.

In vivo comparison of the accuracy of two electronic apex locators

The aim of this study was to analyse in vivo the accuracy of two apex locators, Root ZX and Novapex, to determine the position of the apical constriction. Twenty-three human single-rooted teeth to be extracted for periodontal reasons constituted the experiment. Endodontic access was obtained and the apical constriction was determined by one of the apex locators after initial crown-down preparation. When the electronic marker indicated that the tip of the endodontic file was at the apical constriction, the teeth were filled with composite and then surgically removed. The presence of the endodontic file tip at the apical constriction was evaluated stereomicroscopically (30×) and confirming radiographs were exposed. The accuracy of Root ZX and Novapex was 91.7% and 81.8% respectively. Within the limits of this study, the evaluated apex locators have a similar clinical performance for the apical constriction location.

Chromosome diversity and evolution in tribe Lilieae (Liliaceae) with emphasis on Chinese species

In this paper, karyotype data of the tribe Lilieae in China were analyzed and been superimposed onto a phylogenetic framework constructed by the internal transcribed spacer to investigate the karyotype evolution. Ten parameters for analyzing karyotype asymmetry were assessed and karyotypic idiogram of five genera of Lilieae were illustrated. The results showed that, the relationship of genera in Lilieae that inferred from Maximum Parsimony criteria and Bayesian Inference were congruent with previous studies, which focused on higher level of Liliales. The karyotype showed distinctive among genera, mainly expressed on the location and amount of secondary constrictions and intercalary satellites: the genus Notholirion have neither of them, and the genera Cardiocrinum and Fritillaria have the secondary constriction alone; the genera Lilium and Nomocharis showed both features, and the distribute pattern of the intercalary satellites showed similarity among related clades. The asymmetry that assessed by several methods indicated that the evolution trend of Lilieae did not follow a single direction, but different in each genus. On the sectional level of the genus Lilium (including Nomocharis) the karyotype evolution included three major periods. Combining the chromosomal structure variations and karyotype asymmetry, the chromosome diversity and evolution in Lilieae were quite clear in the light of molecular inference.

Ultrasound analysis of the Czech phoneme /ř/.

Previous studies comparing the articulation of the contrasting Czech trills /ř/ and /r/ have described /ř/ as being produced with the laminal portion of the tongue at a more anterior location with a narrower channel [Ladefoged and Maddieson, The Sounds of the World’s Languages Blackwell, Oxford (1996)] and using a tighter constriction than /r/ [Dankovičová, JIPA 27, 77–80 (1999)]. These observations correspond to the IPA symbol [r] with a raising diacritic, which replaced the former symbol corresponding to a voiced strident apico‐alveolar trill. The current project uses B‐mode and M‐mode ultrasound imaging and acoustics to test these descriptions of /ř/. Preliminary results based on a single participant revealed nearly identical constriction locations for the two trills, with the /ř/ constriction vibrating a larger tongue surface area. Overall, the tongue surface is lower and more forward in the mouth for /ř/ than for /r/, making [r] with a lowering diacritic a more appropriate choice for representing this sound. Spectrographic evidence also reveals important temporal properties for /ř/. Results for additional participants will be reported. [Work supported by the NSERC.]