say

Use say for on-device text-to-speech on macOS.

Siri Natural Voices (recommended)

Siri voices are the best macOS TTS voices but cannot be selected via -v. Instead, run say without -v — it uses the system default voice. Switch languages via defaults write:

# Switch to German
defaults write com.apple.speech.voice.prefs SystemTTSLanguage -string "de"
say "Hallo, wie geht's?" -o output_de.aiff

# Switch to Chinese (Mandarin)
defaults write com.apple.speech.voice.prefs SystemTTSLanguage -string "cmn"
say "你好，世界" -o output_zh.aiff

No process restart needed — the next say invocation picks up the new language immediately.

Prerequisites

Download the desired Siri voices first in System Settings > Accessibility > Spoken Content and set them as the system voice for each language.

Check which voices are currently configured:

defaults read com.apple.Accessibility SpokenContentDefaultVoiceSelectionsByLanguage

Fallback: select voice via -v

For non-Siri voices, use -v directly:

say -v 'Tingting (Enhanced)' "你好，世界"
say -v '?'  # list all installed voices (Siri voices not listed)

Output to file

say -o output.aiff "Hello world"
ffmpeg -y -i output.aiff -ar 22050 -ac 1 output.wav  # convert to WAV

Options

• -v — Select a non-Siri voice
• -r — Speaking rate in words per minute (e.g. -r 150)
• -o — Save to AIFF file instead of playing aloud

Notes

• say adds natural pauses at punctuation — no manual sentence splitting needed
• AIFF is the native output format; convert with ffmpeg for WAV/MP3
• For batch generation: set language once, generate all clips, then switch — minimizes defaults write calls