Browsing by Person "Mooshammer, Christine"

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Devoicing of word-initial stops: A consequence of the following vowel.
(2003) Pape, D.; Mooshammer, Christine; Hoole, Phil; Fuchs, Suzanne
ABSTRACT: The aim of the current study is to investigate the contextual conditions of devoicing of phonologically voiced stops. Therefore articulatory and acoustical data of four male speakers were recorded by means of EMMA and EPG. Devoicing was observed more frequently for the velar stops than for the bilabials. The highest occurrence of devoicing was observed when the voiced stop was followed by a low or mid vowel. To test whether articulatory positions are affected by the identity of the following vowel ANOVAs were computed. All subjects showed significant effects on positional data varying with place of articulation of the stop. Percentage of devoicing was significantly correlated with vertical and horizontal tongue positions for the velar and with the vertical jaw position for both stops. Stepwise regression models were computed to achieve an objective measure for the relevance of the measured parameters. We assume that in German movement economy, i.e. coarticulation, is more important than the maintenance of voicing during the closure, which is in agreement with the view that the voicing distinction in German is primarily produced by a longer VOT for the voiceless stops.
Stress distinction in German: simulating kinematic parameters of tongue-tip gestures.
(Elsevier Science Limited, 2002-07) Mooshammer, Christine; Fuchs, Susanne
Levels of stress are not only distinguished by varying fundamental frequency contours but also by changes of supralaryngeal parameters, e.g., unstressed syllables exhibit reduced movement amplitudes and durations compared with stressed syllables. To investigate the effect of deaccentuation on apical gestures in /tVt/ sequences with all vowels of German, we recorded lingual movements of five speakers by means of EMMA. Movement paths of recorded stressed items were manipulated to simulate kinematic parameters of recorded unstressed items in three different ways: truncation, rescaling and combined truncation and rescaling. We assumed that the simulation type that generated parameters most similar to recorded unstressed items can be interpreted in terms of a generalized motor program for deaccentuation. The following parameters of simulated movements were compared with measured unstressed items: movement durations, peak velocities, distances, interval between velocity peaks in percent of syllable duration, symmetry of velocity profiles and number of acceleration peaks between velocity peaks. Combined simulations resembled most closely the kinematic parameters of unstressed items but could not generate the smaller amplitudes of unstressed syllables with lax vowels, since durational reduction of lax vowels due to deaccentuation was very small, i.e., the spatial reduction was not proportional to the temporal reduction for lax items. Therefore, it can be concluded that with the method used here no single parameter or pattern could be found whose manipulation results in the kinematic characteristics of unstressed syllables, which speaks against the concept of a generalized motor program for deaccentuation.
The Control of Token-to-Token Variability: an Experimental and Modeling Study.
(2001) Mooshammer, Christine; Perrier, Pascal; Fuchs, Susanne; Geng, Christian; Payan, Yohan
The articulatory token-to-token variability in the production of German vowels is investigated with simultaneous EMMA and EPG recordings. The potential role of physical constraints, such as the contacts between tongue and palate measured by EPG, and the biomechanical properties of the tongue, simulated with a 2D finite element model is evaluated. Our results suggest that the control of high front vowels makes use of the palatal contacts, while the variability of low vowels is essentially oriented along the main axis of deformation of the tongue, the high/front-to-low/back direction.
The role of the palate in tongue kinematics: an experimental assessment in VC sequences from EPG and EMMA data.
(2001) Fuchs, Susanne; Perrier, Pascal; Mooshammer, Christine
The effect of palatal contact on tongue tip kinematics was investigated using simultaneous EMMA and EPG recordings. The material consisted of VC sequences, where C is a voiced or voiceless alveolar stop. The kinematic characteristics were studied by analyzing parameters of the velocity profile and the deceleration peaks of the closing gesture. No evidence could be found for a potential influence of lateral contacts. Central contacts, associated with the beginning of the consonantal closure, are strongly correlated in time with the velocity drop. It supports the hypothesis that for achieving a consonantal closure tongue tip kinematics is not controlled by a specific target on the palate, and that its deceleration phase is mostly influenced by the collision with the palate.
WHAT ROLE DOES THE PALATE PLAY IN SPEECH MOTOR CONTROL? INSIGHTS FROM TONGUE KINEMATICS FOR GERMAN ALVEOLAR OBSTRUENTS
(2003) Fuchs, Suzanne; Perrier, Pascal; Geng, Christian; Mooshammer, Christine
ABSTRACT: The tongue moves in a narrow space which influences the speech planning process and affects the kinematic properties of the movement. In order to study the possible role of tongue-palate interaction we investigated tongue tip movement together with tonguepalatal contact patterns by means of simultaneous EMA and EPG recordings. Articulatory data for four German speakers were analyzed. Speech material consisted of VC and VC@ sequences with C being /t/ or /s/ and V being stressed tense /a/ or /u/. The relation between the kinematics of the tongue tip closing gesture and changes in tongue-palatal contact patterns in the anterior, posterior and lateral region were studied. Results for /t/ show a large movement amplitude and a short closing gesture duration whereas in /s/ production the movement amplitude is smaller and the duration longer than in /t/. We conclude that in /t/ the tongue tip hits the palate and this impact stops the movement. In /s/ production we suppose that a precise positioning of the tongue tip is achieved. Speaker dependent tongue-palatal contact patterns can be explained in terms of differences in the palatal shape.