The influence of the palate shape on articulatory token-to-token variability

Articulatory token-to-token variability not only depends on linguistic aspects likethe phoneme inventory of a given language but also on speaker specific morphologi-cal and motor constraints. As has been noted previously (Perkell (1997), Moosham-mer et al. (2004)) , speakers with coronally high ”domeshaped” palates exhibit morearticulatory variability than speakers with coronally low ”flat” palates. One expla-nation for that is based on perception oriented control by the speaker. The influenceof articulatory variation on the cross sectional area and consequently on the acous-tics should be greater for flat palates than for domeshaped ones. This should forcespeakers with flat palates to place their tongue very precisely whereas speakers withdomeshaped palates might tolerate a greater variability. A second explanation couldbeagreateramountoflaterallinguo-palatalcontactforflatpalatesholdingthetonguein position. In this study both hypotheses were tested.Inordertoinvestigatetheinfluenceofthepalateshapeonthevariabilityoftheacous-tic output a modelling study was carried out. Parallely, an EPG experiment wasconducted in order to investigate the relationship between palate shape, articulatoryvariability and linguo-palatal contact.Results from the modelling study suggest that the acoustic variability resulting froma certain amount of articulatory variability is higher for flat palates than for dome-shaped ones. Results from the EPG experiment with 20 speakers show that (1.)speakers with a flat palate exhibit a very low articulatory variability whereas speak-ers with a domeshaped palate vary, (2.) there is less articulatory variability if thereis lots of linguo-palatal contact and (3.) there is no relationship between the amountof lateral linguo-palatal contact and palate shape. The results suggest that there is arelationship between token-to-token variability and palate shape, however, it is not

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