<!--
{
  "availability" : [
    "macOS: 10.3.0 - 14.0.0"
  ],
  "documentType" : "symbol",
  "framework" : "AppKit",
  "identifier" : "/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey",
  "metadataVersion" : "0.1.0",
  "role" : "Structure",
  "symbol" : {
    "kind" : "Structure",
    "modules" : [
      "AppKit"
    ],
    "preciseIdentifier" : "c:@T@NSSpeechPropertyKey"
  },
  "title" : "NSSpeechSynthesizer.SpeechPropertyKey"
}
-->

# NSSpeechSynthesizer.SpeechPropertyKey

These constants are used with [`setObject(_:forProperty:)`](/documentation/AppKit/NSSpeechSynthesizer/setObject(_:forProperty:)) and [`object(forProperty:)`](/documentation/AppKit/NSSpeechSynthesizer/object(forProperty:)) to get or set the characteristics of a synthesizer.

```
struct SpeechPropertyKey
```

## Topics

### Speech Property Keys

[`static let status: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/status)

Get speech-status information for the synthesizer.

[`static let errors: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/errors)

Get speech-error information for the synthesizer.

[`static let inputMode: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/inputMode)

Get or set the synthesizer’s current text-processing mode.

[`static let characterMode: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/characterMode)

Get or set the synthesizer’s current text-processing mode.

[`static let numberMode: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/numberMode)

Get or set the synthesizer’s current number-processing mode.

[`static let rate: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/rate)

Get or set a synthesizer’s speech rate.

[`static let pitchBase: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/pitchBase)

Get or set a synthesizer’s baseline speech pitch.

[`static let pitchMod: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/pitchMod)

Get or set a synthesizer’s pitch modulation.

[`static let volume: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/volume)

Get or set the speech volume for a synthesizer.

[`static let synthesizerInfo: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/synthesizerInfo)

Get information about the speech synthesizer being used on the specified synthesizer.

[`static let recentSync: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/recentSync)

Get the message code for the most recently encountered synchronization command.

[`static let phonemeSymbols: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/phonemeSymbols)

Get a list of phoneme symbols and example words defined for the synthesizer.

[`static let currentVoice: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/currentVoice)

Set the current voice on the synthesizer to the specified voice.

[`static let commandDelimiter: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/commandDelimiter)

Set the embedded speech command delimiter characters to be used for the synthesizer.

[`static let reset: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/reset)

Set a synthesizer back to its default state.

[`static let outputToFileURL: NSSpeechSynthesizer.SpeechPropertyKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/outputToFileURL)

Set the speech output destination to a file or to the computer’s speakers.

### Type Aliases

[`struct CommandDelimiterKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/CommandDelimiterKey)

Keys for the command delimiters.

[`struct ErrorKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/ErrorKey)

Keys that identify errors that may occur during speech synthesis.

[`struct Mode`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/Mode)

Keys for the speaking mode.

[`struct PhonemeInfoKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/PhonemeInfoKey)

Keys for the speech phoneme information.

[`struct StatusKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/StatusKey)

Keys for the speech synthesizier status.

[`struct SynthesizerInfoKey`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/SynthesizerInfoKey)

Keys for the speech synthesizier information.

### Initializers

[`init(rawValue: String)`](/documentation/AppKit/NSSpeechSynthesizer/SpeechPropertyKey/init(rawValue:))

## Relationships

### Conforms To

[`RawRepresentable`](/documentation/Swift/RawRepresentable)

[`Sendable`](/documentation/Swift/Sendable)

[`Hashable`](/documentation/Swift/Hashable)

[`SendableMetatype`](/documentation/Swift/SendableMetatype)

[`Equatable`](/documentation/Swift/Equatable)

---

Copyright &copy; 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)