Speech Runtime

This page covers speech synthesis, transcription, and voice-profile management.

Public surface

• mere.run speech synthesize
• mere.run speech transcribe
• mere.run speech profile list
• mere.run speech profile create
• mere.run speech profile delete

Model families

Text-to-speech

• speech-tts-qwen3-nano
• speech-tts-qwen3-customvoice

Speech-to-text

• speech-asr-qwen3
• speech-asr-parakeet

Typical workflows

Synthesize speech

swift run mere.run speech synthesize \
  "Hello from mere.run" \
  --output ./hello.wav

Transcribe audio

swift run mere.run speech transcribe ./hello.wav --backend auto

Manage voice profiles

swift run mere.run speech profile list
swift run mere.run speech profile create ./reference.wav --name narrator
swift run mere.run speech profile delete narrator

Runtime entrypoints

CLI

• Sources/MereRunCLI/Commands/SpeechSynthesizeCommand.swift
• Sources/MereRunCLI/Commands/SpeechTranscribeCommand.swift
• Sources/MereRunCLI/Commands/SpeechProfileListCommand.swift
• Sources/MereRunCLI/Commands/SpeechProfileCreateCommand.swift
• Sources/MereRunCLI/Commands/SpeechProfileDeleteCommand.swift

TTS runtime

• Sources/AudioTTS/Qwen3TTS/Qwen3TTSGenerator.swift
• Sources/AudioTTS/Qwen3TTS/Qwen3TTSGenerator+Loading.swift
• Sources/AudioTTS/Qwen3TTS/Qwen3TTSGenerator+Generation.swift
• Sources/AudioTTS/Qwen3TTS/Qwen3TTSGenerator+Support.swift

Tokenizer internals:

• Sources/AudioTTS/Qwen3TTS/Qwen3TTSSpeechTokenizer.swift
• Sources/AudioTTS/Qwen3TTS/Qwen3TTSSpeechTokenizer+Encoder.swift
• Sources/AudioTTS/Qwen3TTS/Qwen3TTSSpeechTokenizer+Decoder.swift

STT runtime

• Sources/AudioSTT/Qwen3ASR/Qwen3ASRGenerator.swift
• Sources/AudioSTT/Parakeet/ParakeetGenerator.swift

How speech synthesis flows

At a high level:

1. the CLI resolves the chosen TTS model
2. optional profile or voice configuration is loaded
3. text is converted into the model’s intermediate token representation
4. the generator produces waveform data
5. audio is written to disk through the codec/output helpers

How transcription flows

1. audio input is decoded into the expected local format
2. the selected backend loads its model components
3. the backend produces a transcript
4. the CLI prints or writes the output

Notes for contributors

• speech code spans both AudioTTS and AudioSTT; do not assume it all lives under MereRunCore
• profile management is CLI-facing but depends on the same canonical model and model-store conventions as the rest of the repo

See Architecture Reading Map for a recommended reading order.