init?(voice: NSSpeechSynthesizer .VoiceName ?) Initializes the receiver with a voice.
ClassNSSpeech
NSSpeechSynthesizer
The Cocoa interface to speech synthesis in macOS.
macOS 10.3–14.0Deprecated
class NSSpeechSynthesizerOverview
Speech synthesis, also called text-to-speech (TTS), parses text and converts it into audible speech. It offers a concurrent feedback mode that can be used in concert with or in place of traditional visual and aural notifications. For example, your application can use a speech synthesizer object to “pronounce” the text of important alert dialogs. Synthesized speech has several advantages. It can provide urgent information to users without forcing them to shift attention from their current task. And because speech doesn’t rely on visual elements for meaning, it is a crucial technology for users with vision or attention disabilities.
In addition, synthesized speech can help save system resources. Because sound samples can take up large amounts of room on disk, using text in place of sampled sound is extremely efficient, and so a multimedia application might use an NSSpeech object to provide a narration of a QuickTime movie instead of including sampled-sound data on a movie track.
When you create an NSSpeech instance using the default initializer (init), the class uses the default voice selected in System Preferences > Speech. Alternatively, you can select a specific voice for an NSSpeech instance by initializing it with init(voice:). To begin synthesis, send either start or start to the instance. The former generates speech through the system’s default sound output device; the latter saves the generated speech to a file. If you wish to be notified when the current speech concludes, set the delegate property and implement the delegate method speech.
Speech synthesis is just one of the macOS speech technologies. The speech recognizer technology allows applications to “listen to” text spoken in U.S. English; the NSSpeech class is the Cocoa interface to this technology. Both technologies provide benefits for all users, and are particularly useful to those users who have difficulties seeing the screen or using the mouse and keyboard.
Speech Feedback Window
The speech feedback window (Figure 1) displays the text recognized from the user’s speech and the text from which an NSSpeech object synthesizes speech. Using the feedback window makes spoken exchange more natural and helps the user understand the synthesized speech.
For example, your application may use an NSSpeech object to listen for the command “Play some music.” When it recognizes this command, your application might then respond by speaking “Which artist?” using a speech synthesizer.
When Uses is true, the speech synthesizer uses the feedback window if its visible, which the user specifies in System Preferences > Speech.
Topics
var delegate: (any NSSpeechSynthesizerDelegate )? The synthesizer’s delegate.
protocol NSSpeechSynthesizerDelegate A set of optional methods implemented by delegates of
NSSpeechSynthesizer objects.var usesFeedbackWindow : Bool Indicates whether the receiver uses the speech feedback window.
func voice() -> NSSpeechSynthesizer .VoiceName ? Returns the identifier of the receiver’s current voice.
func setVoice (NSSpeechSynthesizer .VoiceName ?) -> Bool Sets the receiver’s current voice.
var rate: Float The synthesizer’s speaking rate (words per minute).
var volume: Float The synthesizer’s speaking volume.
func addSpeechDictionary ([NSSpeechSynthesizer .DictionaryKey : Any]) Registers the given speech dictionary with the receiver.
struct DictionaryKey These constants identify key-value pairs used to add vocabulary to the dictionary using
addSpeechDictionary(_:) .func object(forProperty : NSSpeechSynthesizer .SpeechPropertyKey ) throws -> Any Provides the value of a receiver’s property.
func setObject (Any?, forProperty : NSSpeechSynthesizer .SpeechPropertyKey ) throws Specifies the value of a receiver’s property.
struct SpeechPropertyKey These constants are used with
setObject(_:forProperty:) and object(forProperty:) to get or set the characteristics of a synthesizer.struct CommandDelimiterKey Keys for the command delimiters.
struct ErrorKey Keys that identify errors that may occur during speech synthesis.
struct Mode Keys for the speaking mode.
struct PhonemeInfoKey Keys for the speech phoneme information.
struct StatusKey Keys for the speech synthesizier status.
struct SynthesizerInfoKey Keys for the speech synthesizier information.
struct VoiceGender The following constants define voice gender attributes, which are the allowable values of the
gender key returned by attributes(forVoice:) .class var availableVoices : [NSSpeechSynthesizer .VoiceName ] Provides the identifiers of the voices available on the system.
class func attributes(forVoice : NSSpeechSynthesizer .VoiceName ) -> [NSSpeechSynthesizer .VoiceAttributeKey : Any] Provides the attribute dictionary of a voice.
class var defaultVoice : NSSpeechSynthesizer .VoiceName Provides the identifier of the default voice.
struct VoiceAttributeKey The following constants are keys for the dictionary returned by
attributes(forVoice:) .class var isAnyApplicationSpeaking : Bool A Boolean value indicating whether any application is currently speaking through the sound output device.
var isSpeaking : Bool Indicates whether the receiver is currently generating synthesized speech.
func startSpeaking (String) -> Bool Begins speaking synthesized text through the system’s default sound output device.
func startSpeaking (String, to: URL) -> Bool Begins synthesizing text into a sound (AIFF) file.
func pauseSpeaking (at: NSSpeechSynthesizer .Boundary) Pauses synthesis in progress at a given boundary.
func continueSpeaking () Resumes synthesis.
func stopSpeaking () Stops synthesis in progress.
func stopSpeaking (at: NSSpeechSynthesizer .Boundary) Stops synthesis in progress at a given boundary.
enum Boundary These constants are used to indicate where speech should be stopped and paused. See
pauseSpeaking(at:) and stopSpeaking(at:) .func phonemes(from: String) -> String Provides the phoneme symbols generated by the given text.
See Also
class NSSpeechRecognizer The Cocoa interface to speech recognition in macOS.
Current page is NSSpeechSynthesizer