A pilot experiment on the effects of an acoustically applied reduced speech signal on speechreading

The aim of this study was to investigate how speechreading of short sentences could be enhanced by presenting the acoustic signal with real-time extracted supplementary speech features. The features were second format frequency and voiceless frication. A group of 10 normal-hearing subjects participated in a simulation experiment. Speechreading performance increased from 22.2% for speechreading only (pretraining), to 61.5% for speechreading plus supplementary auditory information (post-training). The gain from the acoustic information turned out to be larger for subjects who also performed better in the speechreading-only condition. No significant effect was found for the training volume (i.e. 30 minutes versus 5 hours).