Begins speaking a buffer of text.


OSErr SpeakText(SpeechChannel chan, const void *textBuf, unsigned long textBytes);



The speech channel through which speech is to be spoken.


A pointer to the first byte of text to spoken.


The number of bytes of text to spoken.

Return Value

A result code. See Result Codes.


Like SpeakString, the SpeakText function also generates speech, but through a speech channel through which you can exert control over the generated speech.

The SpeakText function converts the text stream specified by the textBuf and textBytes parameters into speech using the voice and control settings for the speech channel chan, which should be created with the NewSpeechChannel function. The speech is generated asynchronously. This means that control is returned to your application before the speech has finished (and probably even before it has begun). The maximum length of the text buffer that can be spoken is limited only by the available RAM.

If SpeakText is called while the channel is currently busy speaking the contents of a prior text buffer, it immediately stops speaking from the prior buffer and begins speaking from the new text buffer as soon as possible. If you pass a zero-length string (or, in C, a null pointer) to SpeakText, the Speech Synthesis Manager stops all speech currently being synthesized by the speech channel specified in the chan parameter without generating additional speech.

The text buffer must be locked in memory and must not move while the Speech Synthesis Manager processes it. This buffer is read at interrupt time, and moving it could cause a system crash. If your application defines a text-done callback function, then it can move the text buffer or dispose of it once the callback function is executed.

See Also

Starting, Stopping, and Pausing Speech


Resumes speech paused by the PauseSpeechAt function.


Pauses speech on a speech channel.


Speaks a buffer of text, using certain flags to control speech behavior.


Begins speaking a text string.


Begins speaking a string represented as a CFString object.


Terminates speech immediately on the specified channel.


Terminates speech delivery on a specified channel either immediately or at the end of the current word or sentence.