Jana Brunner

On the relationship between palate shape and articulatory behavior

In this study the acoustic and articulatory variabilities of speakers with different palate shapes were compared. Since the cross-sectional area of the vocal tract changes less for a slight change in tongue position if the palate is domeshaped than if it is flat, the acoustic variability should be greater for flat palates than for domeshaped ones. Consequently, it can be hypothesized that speakers with flat palates should reduce their articulatory variability in order to keep the acoustic output constant. This hypothesis was tested on 32 speakers recorded via electropalatography (EPG) and acoustics. The articulatory and acoustic variability of some of their vowels and /j/ was measured. Indeed, the results show that the speakers with flat palates reduce their variability in tongue height. There is no such trend in acoustic variability.

Temporal and spatial aspects concerning the realizations of the voicing contrast in German alveolar and postalveolar fricatives

This study investigates the phonetic realizations of voicing contrast in alveolar and postalveolar fricatives production in different word positions in order to understand the temporal and spatial production strategies used in the control of voicing and frication, and to provide a frame of reference for speech therapy despite the inter-speaker variation. Seven native speakers of German, originally coming from various regions, participated in the experiment. Acoustic signals were recorded onto DAT, and tongue palate contact patterns were recorded by means of electropalatography (EPG). The temporal parameters were measured using the acoustic signals and the spatial parameters were measured based on the EPG data. The corpus included real words with // occurring at word initial, medial and final positions. Temporal results showed that differences in the overall frication duration for voicing contrast occur at almost all positions (with longer duration for voiceless phonemes). However, voicing during the frication interval was a less reliable discriminator, particularly for Southern German speakers and at word final position. We found a positive correlation between the relative voicing duration and the amount of tongue palate contact for subjects who produced voicing. Especially for the postalveolars, voicing also coincides with more front articulation. Results are discussed with respect to laryngeal-oral co-ordination and aerodynamics.

Inter-speaker articulatory variability during vowel-consonant-vowel sequences in twins and unrelated speakers

The purpose of this study is to examine and compare the amount of inter-speaker variability in the articulation of monozygotic twin pairs (MZ), dizygotic twin pairs (DZ), and pairs of unrelated twins with the goal of examining in greater depth the influence of physiology on articulation. Physiological parameters are assumed to be very similar in MZ twin pairs in contrast to DZ twin pairs or unrelated speakers, and it is hypothesized that the speaker specific shape of articulatory looping trajectories of the tongue is at least partly dependent on biomechanical properties and the speakers individual physiology. By means of electromagnetic articulography (EMA), inter-speaker variability in the looping trajectories of the tongue back during /VCV/ sequences is analyzed. Results reveal similar looping patterns within MZ twin pairs but in DZ pairs differences in the shape of the loop, the direction of the upward and downward movement, and the amount of horizontal sliding movement at the palate are found.

Motor equivalent strategies in the production of German /∫/ under perturbation.

The German sibilant /∫/ is produced with a constriction in the postalveolar region and often with protruded lips. By covarying horizontal lip and tongue position speakers can keep a similar acoustic output even if the articulation varies. This study investigates whether during two weeks of adaptation to an artificial palate speakers covary these two articulatory parameters, whether tactile landmarks have an influence on the covariation and to what extent speakers can foresee the acoustic result of the covariation without auditory feedback. Six German speakers were recorded with EMA. Four of them showed a covariation of lip and tongue, which is consistent with the motor equivalence hypothesis. The acoustic output, however, does not stay entirely constant but varies with the tongue position. The role of tactile landmarks is negligible. To a certain extent, speakers are able to adapt even without auditory feedback.

Timing of German onset and word boundary clusters

Abstract Previous studies suggest that there are special timing relations in syllable onsets. The consonants are assumed to be timed, on the one hand, with the vocalic nucleus and, on the other hand, with each other. These competing timing relations result in the C-center effect. However, the C-center effect has not consistently been found in languages with complex onsets. Moreover, it has occasionally been found in languages disallowing complex onsets. The present study investigates onset timing in German while discussing alternative explanations (not related to bonding) for the timing patterns observed. Six German speakers were recorded via Electromagnetic Articulography. The corpus contained items with four clusters (/sk/, /kv/, /gl/, and /pl/). The clusters occur in word-initial position, word-medial position, and across a word boundary preceding different vowels. The results suggest that segmental properties (i.e., oral-laryngeal coordination, coarticulatory resistance) determine the observed timing patterns, and specifically the absence or presence of the C-center effect.

Perceptual evidence for allophonic variation of the palatal fricative /ç/ in spontaneous Berlin German.

Auer (2004) postulates that the multi‐ethnolect Kiezdeutsch (Berlin, Germany) differentiates three realizations of /ɪc/: [ɪc]; [ɪ∫]; [ɪφ]. Acoustic analyzes of 1192 tokens of /c/ from the ZAS‐spontaneous speech database (collected from nine adolescent speakers of the Kiezdeutsch multi‐ethnolect as spoken in Berlin) showed no reliable differences in kurtosis, skewness, cog, or peak between items impressionistically categorized into these three groups. Further, in the spontaneous speech of middle‐aged monolingual speakers of the local Berlin dialect [∫] variants of /c/ were also detected, although here this alternation is not attested. The hypotheses are (1) that Berlin‐German also has [∫] as an allophonic variant of /c/ and (2) that Kiezdeutsch has a 3‐way‐split of this category. To evaluate the perceptual validity of these assumptions, tests are being conducted asking native Berliners to rate the category membership of excised variant realizations of /c/ and /∫/ from the Kiezdeutsch‐ and Berlin‐database o...

Correlation between angle of incidence and sliding patterns of the tongue along the palate in Korean velar stops

In former studies, it has been hypothesized that the articulatory production of oral stops could result from the interaction between the tongue moving towards a virtual target located above the palate, and the palate. Velar stops, where the tongue slides along the palate during the occlusion phase, offer a nice experimental framework for further experimental assessments. Indeed, in the framework of the ‘‘virtual target’’ hypothesis, the sliding movement should be seen as the continuation of the movement before the occlusion, but constrained by the palate. Hence, relations should exist between the movement characteristics before contact and during the occlusion phase. To test this hypothesis three Korean speakers were recorded via EMA producing /aCV/ sequences with C=/g/, /k’/ and /kh/, V=/a/, /i/ or /u/. The angle between tongue trajectory just before the impact and palatal contour was estimated, and the amplitude of the sliding movement was measured. Preliminary results for two speakers show that these t...

Motor equivalent strategies in the production of /u/ in perturbed speech

Several articulatory strategies are available during the production of /u/, all resulting in a similar acoustic output. For example, speakers can protrude the lips and compensate for that by widening the velar constriction. This study investigates whether speakers use this relation under perturbation. Five speakers were provided with palatal prostheses which were worn for two weeks. Speakers were instructed to make a serious attempt to produce normal speech. Their speech was recorded via EMA and acoustics several times over the adaptation period. Formant values of /u/‐productions were measured. Velar constriction width and lip protrusion were estimated. For four speakers a correlation between constriction width and lip protrusion was found. A correlation between lip protrusion and F1 or F2 was rare and no correlation occurred between constriction size and either of the formants. The acoustic output was thus constant. The results show that under perturbation speakers use motor equivalent strategies. The co...

Which Factors Can Explain Individual Outcome Differences When Learning a New Articulatory-to-Acoustic Mapping?

Speech motor learning is characterized by inter-speaker outcome differences where some speakers fail to compensate for articulatory and/or auditory perturbations. Hypotheses put forward to explain these differences entertain the idea that speakers employ auditory and sensorimotor feedback differently depending on their predispositions or different acuity traits. A related idea implies that individual speakers’ traits may further interact with the amount of auditory and somatosensory feedback involved in the production of a specific speech sound, e.g. with the degree of the tongue-palate contact. To investigate these hypotheses, we performed two experiments with an identical group of Russian native speakers where we perturbed vowel and fricative spectra employing identical experimental designs. In both experiments we observe compensatory efforts for all participants. However, among our participants we find neither compelling evidence for individual feedback preferences nor for consistent speaker-internal patterns of the learning outcomes in the context of vowels and fricatives. We suggest that a more plausible explanation for our results is provided by the idea that fricatives and vowels exhibit different degrees of complexity of the articulatory-to-acoustic mapping.