# Within and Across-Language Comparison of Vocal Emotions in Mandarin and English
## 4 Discussion and Conclusions
### Acoustic and Physiological Patterns of Each Vocal Emotion in Mandarin and English  
The results of the within-language comparison showed that all the prosodic cues including f0, duration and intensity were significantly different between emotions in each language, suggesting that different vocal emotions had unique prosodic patterns, which was consistent with previous studies (e.g., [2; 3; 49; 50]). Specifically, happiness and anger showed relatively higher pitch level, greater degree of local pitch fluctuation, faster speech rate and higher intensity in both Mandarin and English, which matched those observed in earlier studies (Mandarin: [15; 20; 51]; English: [7]). Fear had the highest pitch level and fastest speech rate among five emotions. The intensity of fear was also higher but fear had smaller local pitch movements. These results were also consistent with those of [7; 52; 53]. The mean pitch for sadness was close to that of neutral emotion, which was also reported by [54] for Mandarin and [7] for English. In addition, sadness had smaller local pitch movements, slowest speech rate and weakest intensity in both languages. Unlike previous studies that mostly use pitch measures like mean pitch and pitch range to describe the global changes of the pitch contour, it is interesting to note that our study includes more fine pitch-related cues that can quantify the degree of pitch changes over time locally, such as mean absolute slope, rise, fall, rise slope and full slope. Thus, vocal emotions such as happiness and fear and anger and fear can be clearly separated with respect to the degree of local pitch movements. Furthermore, these cues have been proved to be useful to examine whether pitch fluctuation is influenced by the existence of a lexical tone system within one  
Figure 5: Physiological measures of phonation of four emotions in Mandarin and English. Points indicate mean values and error bars 95% confidence intervals (Adapted from Figure 3 in Reference [31]). language [25; 26]. Consequently, we also include them in our across-language analysis to test whether the restriction exists. In addition, our study also analysed a set of spectral cues that could reflect the degree of periodicity, signal to noise ratio (SNR) and spectral tilt in the speech signal [30; 38]. Results of spectrum analysis revealed different patterns in the two languages. In Mandarin, happiness had better periodicity, higher SNR and smaller spectral tilt due to the increased high-frequency energy. Anger showed similar patterns with happiness. Fear had poorest periodicity, smallest SNR and higher spectral tilt caused by lower high-frequency energy. Finally, sadness was less periodical with a smaller SNR and highest spectral tilt caused by the lowest high-frequency energy. In contrast, the periodicity and SNR of five emotions exhibited few differences in English. Happiness had highest high-frequency energy, thus, its spectral tilt was small, followed by anger, sadness and fear in English. The above results of spectrum analysis were meaningful to infer the source feature and to categorize different vocal fold vibration patterns of different vocal emotions. On one hand, periodicity and SNR will be reduced when vocal fold is not completely closed during vibration with airflow goes through, which indicates a breathy voice or an aspirated sound. On the other hand, the spectral tilt can reflect the shape of the glottal wave, which represents the mechanism of vocal fold vibration. A larger spectral tilt can be caused by a breathy voice or a soft voice [30]. Therefore, our results of spectrum analysis suggest that fear and sadness may have breathy voice in Mandarin. Another new approach we used in this study was conducting the EGG experiment to directly detect the physiological mechanism of different vocal emotions as a supplement for spectral measures. Results revealed that neutral and happy were expressed with modal voice in both Mandarin and English. Anger was produced with a small degree of tense voice in Mandarin.