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The present article illustrates that the specific articulatory and aerodynamic requirements for voiced but not voiceless alveolar or dental stops can cause tongue tip retraction and tongue mid lowering and thus retroflexion of front coronals. This retroflexion is shown to have occurred diachronically in the three typologically unrelated languages Dhao (Malayo-Polynesian), Thulung (Sino-Tibetan), and Afar (East-Cushitic). In addition to the diachronic cases, we provide synchronic data for retroflexion from an articulatory study with four speakers of German, a language usually described as having alveolar stops. With these combined data we supply evidence that voiced retroflex stops (as the only retroflex segments in a language) did not necessarily emerge from implosives, as argued by Haudricourt (1950), Greenberg (1970), Bhat (1973), and Ohala (1983). Instead, we propose that the voiced front coronal plosive /d/ is generally articulated in a way that favours retroflexion, that is, with a smaller and more retracted place of articulation and a lower tongue and jaw position than /t/.
This paper shows that several typologically unrelated languages share the tendency to avoid voiced sibilant affricates. This tendency is explained by appealing to the phonetic properties of the sounds, and in particular to their aerodynamic characteristics. On the basis of experimental evidence it is shown that conflicting air pressure requirements for maintaining voicing and frication are responsible for the avoidance of voiced affricates. In particular, the air pressure released from the stop phase of the affricate is too high to maintain voicing, which in consequence leads to a devoicing of the frication part.
Rate effects on aerodynamics of intervocalic stops : evidence from real speech data and model data
(2008)
This paper is a first attempt towards a better understanding of the aerodynamic properties during speech production and their potential control. In recent years, studies on intraoral pressure in speech have been rather rare, and more studies concern the air flow development. However, the intraoral pressure is a crucial factor for analysing the production of various sounds.
In this paper, we focus on the intraoral pressure development during the production of intervocalic stops.
Two experimental methodologies are presented and confronted with each other: real speech data recorded for four German native speakers, and model data, obtained by a mechanical replica which allows reproducing the main physical mechanisms occurring during phonation. The two methods are presented and applied to a study on the influence of speech rate on aerodynamic properties.
This work investigates laryngeal and supralaryngeal correlates of the voicing contrast in alveolar obstruent production in German. It further studies laryngealoral co-ordination observed for such productions. Three different positions of the obstruents are taken into account: the stressed, syllable initial position, the post-stressed intervocalic position, and the post-stressed word final position. For the latter the phonological rule of final devoicing applies in German. The different positions are chosen in order to study the following hypotheses:
1. The presence/absence of glottal opening is not a consistent correlate of the voicing contrast in German.
2. Supralaryngeal correlates are also involved in the contrast.
3. Supralaryngeal correlates can compensate for the lack of distinction in laryngeal adjustment.
Including the word final position is motivated by the question whether neutralization in word final position would be complete or whether some articulatory residue of the contrast can be found.
Two experiments are carried out. The first experiment investigates glottal abduction in co-ordination with tongue-palate contact patterns by means of simultaneous recordings of transillumination, fiberoptic films and Electropalatography (EPG). The second experiment focuses on supralaryngeal correlates of alveolar stops studied by means of Electromagnetic Articulography (EMA) simultaneously with EPG. Three German native speakers participated in both recordings. Results of this study provide evidence that the first hypothesis holds true for alveolar stops when different positions are taken into account. In fricative production it is also confirmed since voiceless and voiced fricatives are most of the time realised with glottal abduction. Additionally, supralaryngeal correlates are involved in the voicing contrast under two perspectives. First, laryngeal and supralaryngeal movements are well synchronised in voiceless obstruent production, particularly in the stressed position. Second, supralaryngeal correlates occur especially in the post-stressed intervocalic position. Results are discussed with respect to the phonetics-phonology interface, to the role of timing and its possible control, to the interarticulatory co-ordination, and to stress as 'localised hyperarticulation'.
This study examines intraoral pressure for English and German stops in bilabial and alveolar place of articulation. Our subjects are two speakers of American English and three speakers of German. VOICING is the main phonological contrast under evaluation in both word initial and word final position. For initial stops, a few of the pressure characteristics showed differences between English and German, but on the whole the results point to similar production strategies at both places of articulation in the two different languages. Analysis of the pressure trajectory differences between VOICING categories in initial position raises questions about articulatory differences. In the initial closing gesture, time from start of gesture to closure is roughly equivalent for both categories, but the pressure change is significantly smaller on average for VOICED stops. Final stops, however, present a more complicated picture. German final stops are neutralized to a presumed VOICELESS phonological state. English final /p/ is broadly similar to German /p/, but English /t/ often shows no pressure increase at all which is at odds with the conventional account of phonation termination via pressure increase and loss of pressure differential. The results raise the question of whether the German final stops should be considered VOICELESS or some intermediate form, at least as compared to English final stops.
Studying kinematic behavior in speech production is an indispensable and fruitful methodology in order to describe for instance phonemic contrasts, allophonic variations, prosodic effects in articulatory movements. More intriguingly, it is also interpreted with respect to its underlying control mechanisms. Several interpretations have been borrowed from motor control studies of arm, eye, and limb movements. They do either explain kinematics with respect to a fine tuned control by the Central Nervous System (CNS) or they take into account a combination of influences arising from motor control strategies at the CNS level and from the complex physical properties of the peripheral speech apparatus. We assume that the latter is more realistic and ecological. The aims of this article are: first, to show, via a literature review related to the so called '1/3 power law' in human arm motor control, that this debate is of first importance in human motor control research in general. Second, to study a number of speech specific examples offering a fruitful framework to address this issue. However, it is also suggested that speech motor control differs from general motor control principles in the sense that it uses specific physical properties such as vocal tract limitations, aerodynamics and biomechanics in order to produce the relevant sounds. Third, experimental and modelling results are described supporting the idea that the three properties are crucial in shaping speech kinematics for selected speech phenomena. Hence, caution should be taken when interpreting kinematic results based on experimental data alone.
The present article illustrates that the specific articulatory and aerodynamic requirements for voiced but not voiceless alveolar or dental stops can cause tongue tip retraction and tongue mid lowering and thus retroflexion of front coronals. This retroflexion is shown to have occurred diachronically in the three typologically unrelated languages Dhao (Malayo-Polynesian), Thulung (Sino-Tibetan), and Afar (East-Cushitic). In addition to the diachronic cases, we provide synchronic data for retroflexion from an articulatory study with four speakers of German, a language usually described as having alveolar stops. With these combined data we supply evidence that voiced retroflex stops (as the only retroflex segments in a language) did not necessarily emerge from implosives, as argued by Haudricourt (1950), Greenberg (1970), Bhat (1973), and Ohala (1983). Instead, we propose that the voiced front coronal plosive /d/ is generally articulated in a way that favours retroflexion, that is, with a smaller and more retracted place of articulation and a lower tongue and jaw position than /t/.
Proper speech production requires auditory speech feedback control. Models of speech production associate this function with the right cerebral hemisphere while the left hemisphere is proposed to host speech motor programs. However, previous studies have investigated only spectral perturbations of the auditory speech feedback. Since auditory perception is known to be lateralized, with right-lateralized analysis of spectral features and left-lateralized processing of temporal features, it is unclear whether the observed right-lateralization of auditory speech feedback processing reflects a preference for speech feedback control or for spectral processing in general. Here we use a behavioral speech adaptation experiment with dichotically presented altered auditory feedback and an analogous fMRI experiment with binaurally presented altered feedback to confirm a right hemisphere preference for spectral feedback control and to reveal a left hemisphere preference for temporal feedback control during speaking. These results indicate that auditory feedback control involves both hemispheres with differential contributions along the spectro-temporal axis.
As has been noted previously, speakers with coronally low "flat" palates exhibit less articulatory variability than speakers with coronally high "domeshaped" palates. This phenomenon is investigated by means of a tongue model and an EPG experiment. The results show that acoustic variability depends on the shape of the vocal tract. The same articulatory variability leads to more acoustic variability if the palate is flat than if it is domeshaped. Furthermore, speakers with domeshaped palates show more articulatory variability than speakers with flat palates. The results are explained by different control strategies by the speakers. Speakers with flat palates reduce their articulatory variability in order to keep their acoustic variability low.
Articulatory token-to-token variability not only depends on linguistic aspects like the phoneme inventory of a given language but also on speaker specific morphological and motor constraints. As has been noted previously (Perkell (1997), Mooshammer et al. (2004)), speakers with coronally high "domeshaped" palates exhibit more articulatory variability than speakers with coronally low "flat" palates. One explanation for that is based on perception oriented control by the speaker. The influence of articulatory variation on the cross sectional area and consequently on the acoustics should be greater for flat palates than for domeshaped ones. This should force speakers with flat palates to place their tongue very precisely whereas speakers with domeshaped palates might tolerate a greater variability. A second explanation could be a greater amount of lateral linguo-palatal contact for flat palates holding the tongue in position. In this study both hypotheses were tested.
In order to investigate the influence of the palate shape on the variability of the acoustic output a modelling study was carried out. Parallely, an EPG experiment was conducted in order to investigate the relationship between palate shape, articulatory variability and linguo-palatal contact.
Results from the modelling study suggest that the acoustic variability resulting from a certain amount of articulatory variability is higher for flat palates than for domeshaped ones. Results from the EPG experiment with 20 speakers show that (1.) speakers with a flat palate exhibit a very low articulatory variability whereas speakers with a domeshaped palate vary, (2.) there is less articulatory variability if there is lots of linguo-palatal contact and (3.) there is no relationship between the amount of lateral linguo-palatal contact and palate shape. The results suggest that there is a relationship between token-to-token variability and palate shape, however, it is not that the two parameters correlate, but that speakers with a flat palate always have a low variability because of constraints of the variability range of the acoustic output whereas speakers with a domeshaped palate may choose the degree of variability. Since linguo-palatal contact and variability correlate it is assumed that linguo-palatal contact is a means for reducing the articulatory variability.