Sets the speech rate of a designated speech channel.


func SetSpeechRate(_ chan: SpeechChannel, _ rate: Fixed) -> OSErr



The speech channel whose rate you wish to set.


The new speech rate in words per minute, expressed as an integer value.

Return Value

A result code. See Result Codes.


The SetSpeechRate function adjusts the speech rate on the speech channel specified by the chan parameter to the rate specified by the rate parameter. As a general rule, speaking rates range from around 150 words per minute to around 220 words per minute. It is important to keep in mind, however, that users will differ greatly in their ability to understand synthesized speech at a particular rate based upon their level of experience listening to the voice and their ability to anticipate the types of utterances they will encounter.

Note: the new speech rate should be expressed as an integer (not a fixed point decimal number as the data type implies).

See Also

Changing Speech Attributes

func SetSpeechProperty(SpeechChannel, CFString, CFTypeRef?) -> OSErr

Sets the value of the specified speech-channel property.

func SetSpeechPitch(SpeechChannel, Fixed) -> OSErr

Sets the speech pitch on a designated speech channel.