Transplanting Credibility into a Foreign Voice. An Experiment on Synthesized L2 Italian

This study intends to verify through perceptual tests conducted on original and artificially modified speech whether a relationship exists among the degree of comprehensibility of an utterance, the foreign accent and the credibility of the message. Four bizarre-but-true news read in Italian by four non-native speakers were artificially modified with Praat and WaveSurfer. Each piece of news was transplanted, so that segmental and prosodic features of a text read by a native speaker were transferred onto the same text uttered by a non-native speaker. The corpus was administered to 265 native Italian listeners, who were requested to indicate the degree of comprehensibility, the level of foreign accent and the truthfulness of each item. The results point out the existence of a close inverse relationship between comprehensibility and credibility. The presence of foreign accent, providing an impediment to the understanding of the message, tends to create an attitude of distrust in the listener. The most important features for the foreign accent reduction are the suprasegmental ones and, in particular, the durations of the phones and the pitch movement.