iOS Developer Library


AV Foundation Framework Reference AVSpeechSynthesizerDelegate Protocol Reference

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The AVSpeechSynthesizerDelegate protocol defines methods that the delegate of an AVSpeechSynthesizer object may implement; all methods in this protocol are optional. You can implement these methods to respond to events that occur during speech synthesis.

Delegate messages are sent by the synthesizer for three categories of events:

  • When speech pauses or resumes

  • When the synthesizer starts or finishes speaking a block of text (as encapsulated by an AVSpeechUtterance object)

  • As the synthesizer produces each individual unit of speech

For the third case, you can implement speechSynthesizer:willSpeakRangeOfSpeechString:utterance: to provide a user interface in which each word is visibly highlighted as it is spoken.