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ISpVoice::SetRate (SAPI 5.4)

Microsoft Speech API 5.4


ISpVoice::SetRate retrieves the current text rendering rate adjustment. The default rate for a voice is set through Speech properties in Control Panel.

    HRESULT SetRate(
   long   RateAdjust


  • RateAdjust
    [in] Value specifying the speaking rate of the voice. Supported values range from -10 to 10 - values outside this range may be truncated.

Return values



Voices do not all have the same default rate.

The granularity of the rate is engine dependent.

Applications can adjust the rate of a voice either through this function call, or through XML passed to the voice with the input text of a speak call (see the XML Schema : SAPI white paper). The voice should combine rate adjustments made in these two ways to arrive at a final rate.