Listener detection of talker stress in low-rate coded speech

We describe an experiment where listeners were asked to detect two specific forms of stress in talkers' recorded voices heard via six different simulated communication systems. Both task-induced stress and dramatized urgency were used. Communication systems included low-rate digital speech coding combined with bit errors, packet loss, and packet loss concealment. Twenty-four listeners participated in a total of 11,520 detection trials. A parallel investigation of word intelligibility in sentence context used 576 trials. Intelligibility results showed wide variance due to communication system and stress detection results showed less variance. More specifically, we found that listener detection of dramatized talker urgency was 4.7 times more robust to communication system degradations than word intelligibility in sentence context.