Make the `say` terminal utility and NSSpeechSynthesizer work with Siri voices

Question

The say command-line utility seems to be unaware of Siri voices as of macOS 11 (Big Sur):
- say -v '?' doesn't list Siri voices.
- Targeting a Siri voice explicitly doesn't work:
  - say -v NoraSiri hi! doesn't find the Nora Siri voice (which is the default Siri voice).
- Using a bundle ID (e.g., com.apple.speech.synthesis.voice.custom.siri.nora.premium)^[1] doesn't complain about an unknown voice, but speech output fails with Open speech channel failed: -86:
  - say -v com.apple.speech.synthesis.voice.custom.siri.nora.premium hi!
  - Seemingly, any string with prefix com.apple.speech.synthesis.voice.custom triggers this error.
Similarly, NSSpeechSynthesizer doesn't list Siri voices as available and doesn't support selecting one for speech output.

macOS Big Sur itself is capable of using a Siri voice for TTS, as evidenced by the fact that you can select one as the system voice in System Preferences > Accessibility > Speech, e.g. in combination with the shortcut-key-based Speak selected text when the key is pressed feature.
(Curiously, though, a Siri voice selected as the system voice does not take effect if you right-click text and select Speech > Start Speaking from the context menu and possibly also not for other accessibility features - this discrepancy is the subject of this MacRumors forum thread.)

Unfortunately, it appears that this functionality isn't exposed through a utility or API.

Is there any way to use Siri voices with say or NSSpeechSynthesizer?

[1] The bundle IDs of the installed Siri voices can be determined as follows:

ls /System/Library/Speech/Voices/*.SpeechVoice/Contents/Info.plist | grep -i siri | xargs -n 1 /usr/libexec/PlistBuddy -c 'print CFBundleIdentifier'

^{Note: The above works for me as of macOS Big Sur, upgraded from an earlier version, with at least one Siri voice installed. Siu Ching Pong -Asuka Kenji- reports that on a freshly installed, non-upgraded Big Sur machine the System/Library/Speech/Voices directory is empty.}

To find the bundle IDs of all available (downloadable) Siri voices:

/usr/libexec/PlistBuddy -c 'print DownloadableCustomVoices' /System/Library/PrivateFrameworks/SpeechObjects.framework/Resources/SpeechDataDefaults.plist | grep 'VoiceIdentifier' | sed -E 's/.+ = //'

I am testing your command for listing bundle IDs. It does not work on my machine (macOS Big Sur Version 11.4). The directory /System/Library/Speech/Voices/ is empty. It seems that the files are moved to /System/Library/SpeechBase/Voices/. However, the files for Siri are not found there (grep does not match anything). — Siu Ching Pong -Asuka Kenji-
On my machine (macOS Big Sur Version 11.4), the voice identifiers for Siri could be found inside the file /System/Library/PrivateFrameworks/SpeechObjects.framework/Versions/A/Resources/SpeechDataDefaults.plist. — Siu Ching Pong -Asuka Kenji-
That is curious, @SiuChingPong-AsukaKenji-: For me, the original command still works, as of macOS Big Sur 11.5.1 — mklement0
Perhaps it is because mine is a clean install of macOS Big Sur. When I installed Big Sur, I wiped out all the things on my Mac. The fact that your command still works on your machine may be due to upgrading from a previous version of macOS. Those files are carried from the old one. By the way, I am curious whether my locations work on your machine too. 😉 — Siu Ching Pong -Asuka Kenji-
@SiuChingPong-AsukaKenji-: indeed, my machine is upgraded, but please note that your file - also present in earlier versions - is just a catalog of metadata about downloadable voices, whereas my command lists only the installed Siri voices. I've added a command to extract the bundle IDs of all downloadable Siri voices too. (As an aside: /System/Library/PrivateFrameworks/SpeechObjects.framework/Resources/SpeechDataDefaults.plist is the better path to use (/Versions/A removed). — mklement0

Jonathan Dagle Jonathan Dagle · Accepted Answer · 2020-07-01T15:48:51

In a WWDC20 talk, Apple says Siri voices are not available in AVSpeechSynthesizer.

The talk is called "Create a seamless speech experience in your apps." Apparently this applies to Catalina as well.

Here's the relevant slide:

WWDC20 Slide

I started a thread at macrumors regarding similar problems configuring the system voice to speak text.

Make the `say` terminal utility and NSSpeechSynthesizer work with Siri voices

2 Answers