Options for Text-to-speech usage. See the details in the official specs.
Voice sentiment. Works only with Yandex voices and only for ru_RU voices.
Voice pitch. Acceptable ranges: 1) the numbers followed by "Hz" from 0.5Hz to 2Hz 2) x-low, low, medium, high, x-high, default
Speech speed. Possible values are x-slow, slow, medium, fast, x-fast, default.
Speech volume. Possible values are silent, x-soft, soft, medium, loud, x-loud, default.
If you have a custom Yandex engine voice, specify it in this field. Please contact support to activate this feature for your account.