A Phonetic Case Study On Prosodic Variability In Suicidal Emergency Calls

Speech prosody has been applied in numerous speech emotion recognition tasks. Yet, especially in forensic speech science, a need for acoustic-phonetic analyses with human evaluation still exists since many current speech emotion models are trained with speech data wherein emotions are considered as constant states and the dynamic effects of the interlocutor have been disregarded; for instance, during an emergency call, the caller's emotional prosody varies according to the communication with the emergency operator, which causes problems for existing speech emotion models when analysing individual emergency recordings. In this phonetic case study, prosodic variation was investigated in two suicidal emergency calls; eight prosodic features from two adult male callers were analysed before and after hearing the emergency operators' offer to help. In addition, the existence of a possible linear association between the emergency operator's and the caller's prosodic features were evaluated. The results show that caller and operator pitch are negatively correlated (-0.33), and half of callers' prosodic features vary significantly (p < 0.05) after hearing the offer of help.