An acoustic study of vocal emotions in Yoruba

The vocal expression of different emotional states is an essential part of communication. However, vocal emotion in African languages has not attracted much scholarly works. This study investigates the roles of pitch, intensity, and speech rate in the vocal expression of angry, happy, sad, fear, disgust and neutral emotions in Yoruba, a West BenueCongo language spoken predominantly in Southwestern Nigeria. Data were gathered from 12 professional and church actors using utterances that can be expressed in the six different emotional states. The results of the acoustic analysis show that the expression of emotions in Yoruba employs a blend of cues from pitch level, intensity and speech rate. Although the presence of three tones plus a downstep in Yoruba results in a congestion of the tone space thereby placing a limitation on the effects of pitch change in the discrimination of vocal emotions, notable differences in pitch change still exist across the emotional categories. It is concluded that the vocal expression of emotion deploys a complex interaction between pitch, speech rate and intensity.