Page 211 - Designing Sociable Robots

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192 Chapter 11

Table 11.5
The mapping from each expressive quality of speech to the vocal affect parameters (VAPs). There is a single fixed
mapping for each emotional quality.

Vocal Affect Parameter Anger Disgust Fear Happiness Sorrow Surprise Neutral
accent shape 10 0 10 10 −7 9 0
average pitch −10 −10 10 3 −7 6 0
contour slope 10 0 10 0 0 10 0
final lowering 10 5 −10 −4 8 −10 0
pitch range 10 5 10 10 −10 10 0
reference line −10 0 10 −8 −1 −8 0
speech rate 4 −8 10 3 −6 6 0
stress frequency 0 0 10 5 1 0 0
breathiness −5 0 0 −5 0 −9 0
brillance 10 5 10 −2 −6 9 0
laryngealization 0 0 −10 0 0 0 0
loudness 10 −5 10 8 −5 10 0
pause discontinuity 10 0 10 −10 −8 −10 0
pitch discontinuity 3 10 10 6 0 10 0
precision of articulation 10 7 0 −3 −5 0 0

Timing
The vocal affect timing parameters contribute to speech rhythm. Such correlates arise in
emotional speech from physiological changes in respiration rate (changes in breathing
patterns) and level of arousal.
• Speech Rate Controls the rate of words or syllables uttered per minute. It influences how
quickly an individual word or syllable is uttered, the duration of sound to silence within an
utterance, and the relative duration of phoneme classes. Speech is faster with higher arousal
and slower with lower arousal. This parameter varies directly with DECtalk’s speech-rate
setting. It varies inversely with DECtalk’s period-pause and comma-pause settings as
faster speech is accompanied with shorter pauses.
• Stress Frequency Controls the frequency of occurrence of pitch accents and determines
the smoothness or abruptness of f 0 transitions. As more words are stressed, the speech
sounds more emphatic and the speaker more agitated. It filters other vocal affect parameters
such as precision of articulation and accent shape, and thereby contributes to the associated
DECtalk settings.

Voice Quality

Emotion can induce not only changes in pitch and tempo, but in voice quality as well. These
phenomena primarily arise from changes in the larynx and articulatory tract.