Effects of reduced orosensory feedback on spectral characteristics of medioalveolar /s/

Effects of reduced orosensory feedback on the production of fricative sounds were studied by measuring spectral characteristics of medioalveolar /s/. Five Finnish male speakers produced sibilant /s/ embedded in 8 different word contexts under normal condition and under reduced condition, in which the tactile information from the tongue was reduced by blocking the lingual nerve on the right side by local anesthesia. Parameters of Long Time Average (LTA) spectrum (i.e., center of gravity, standard deviation, skewness, and kurtosis) were measured by Praat software for every speaker. In comparison between the two conditions, center of gravity, standard deviation, skewness, and kurtosis changed for every speaker. However, the changes were variable and individual. The results of acoustic analysis show that reduced tactile sensation have effects on tongue function producing spectral alterations for sibilant /s/. The inter-individual variation between different talkers suggests that there are no general compensatory mechanisms of speech production, but the mechanisms are highly speaker-dependent.