Palatal morphology can influence speaker-specific realizations of phonemic contrasts

The purpose of this study was to further explore the understanding of speaker-specific realizations of the /s/-/ʃ/ contrast in German in relation to individual differences in palate shape.

Two articulatory experiments were carried out with German native speakers. In the first experiment, 4 monozygotic and 2 dizygotic twin pairs were recorded by means of electromagnetic articulography. In the second experiment, 12 unrelated speakers were recorded by means of electropalatography. Interspeaker variability in the articulatory distance between the sibilants was measured and was correlated with several parameters of the palate shape.

The results were twofold: (a) Similar palatal morphologies as found in monozygotic twins yield similar articulatory realizations of the /s/-/ʃ/ contrast regarding vertical and horizontal distance of the target tongue tip positions, and (b) the realization of the contrast was influenced by palatal steepness, especially the inclination angle of the alveolo-palatal region. Speakers with flat inclination angles mainly retracted their tongue to realize the contrast, whereas speakers with steep inclination angles also elevated their tongue.

The articulatory realization of the sibilant contrast is influenced not only by speaker-specific auditory acuity, as previously observed, but also by palatal shape morphology, which affects the somatosensory feedback speakers receive.