The AVSpeech​Synthesizer class produces synthesized speech from text on an iOS device, and provides methods for controlling or monitoring the progress of ongoing speech.


To speak some amount of text, you must first create an AVSpeech​Utterance instance containing the text. (Optionally, you may also use the utterance object to control parameters affecting its speech, such as voice, pitch, and rate.) Then, pass it to the speak(_:​) method on a speech synthesizer instance to speak that utterance.

The speech synthesizer maintains a queue of utterances to be spoken. If the synthesizer is not currently speaking, calling speak(_:​) begins speaking that utterance immediately (or begin waiting through its pre​Utterance​Delay if one is set). If the synthesizer is speaking, utterances are added to a queue and spoken in the order they are received.

After speech has begun, you can use the synthesizer object to pause or stop speech. After speech is paused, it may be continued from the point at which it left off; stopping ends speech entirely, removing any utterances yet to be spoken from the synthesizer’s queue.

You may monitor the speech synthesizer by examining its speaking and paused properties, or by setting a delegate. Messages in the AVSpeech​Synthesizer​Delegate protocol are sent as significant events occur during speech synthesis.


Synthesizing Speech

func speak(AVSpeech​Utterance)

Enqueues an utterance to be spoken.

Controlling Speech Synthesis

func continue​Speaking()

Continues speech from the point at which it left off.

func pause​Speaking(at:​ AVSpeech​Boundary)

Pauses speech at the specified boundary constraint.

var is​Paused:​ Bool

A Boolean value that indicates whether speech has been paused.

var is​Speaking:​ Bool

A Boolean value that indicates whether the synthesizer is speaking.

func stop​Speaking(at:​ AVSpeech​Boundary)

Stops all speech at the specified boundary constraint.

Managing the Delegate

var delegate:​ AVSpeech​Synthesizer​Delegate?

The delegate object for the speech synthesizer.



Constraints describing when speech may be paused or stopped.


Inherits From